Booming Blade being reprinted and nerfed in Tasha's [New Preview Release]

[king_steve]

Perhaps if you are the solo melee combatant in your party. If not, any creature in melee with someone else is rather unlikely to move.

Don't forget your party can also encourage the enemy to trigger the effect as well, for example Flame Sphere, create bonfire or some other effect like that might make an enemy want to move and trigger the Booming blade.

[Dork_Forge]

You have to make an assumption about the rider. I use the treantmonk number of 50%.

So at 5th level:
2 attacks 2d8+8 = 17 damage
1 booming (2d8+4) + (2d8 * 0.5) = 17.5 damage

Assuming that this is meant to be a comparison with Extra Attack classes, it's only favourable to Booming Blade if you are prioritising something other than damage.

At 5th level:

Dueling: 2d8+12= 21 damage

TWF: 3d6+12= 22.5

Then you get into other comparisons, like using a larger weapon, two handing a versatile weapon, Hunter's Mark, Rage damage. If an Extra attack class is only doing 2d8+Mod then they likely don't care about damage to begin with.

[MaxWilson]

Then you get into other comparisons, like using a larger weapon, two handing a versatile weapon, Hunter's Mark, Rage damage. If an Extra attack class is only doing 2d8+Mod then they likely don't care about damage to begin with.

Even if a Cavalier "doesn't care" about damage because he's mostly about tanking, and is happy to do 3x d8+3 (22.5) with his Strength 16, it's still pretty sad for the Cavalier if a Mobile Necromancer 10/Life Cleric 1 is doing d6+5d8+2 (28) with Strength 15 and Booming Blade. Minimal investment by a Fighter still ought to result in more damage than minimal investment by a wizard.

Conceptually I think Booming Blade is great for EKs, but I hate how it interacts with 5E's spellcasting and multiclassing rules. My own personal solution isn't to nerf Booming Blade per se though, I just re-impose AD&D-style penalties for spellcasting in melee. That is, being incapacitated or casting a spell (unless you have Warcaster) allows enemies within range to make an opportunity attack. Warcaster's avoiding that opportunity attack replaces Warcaster's "cast a spell as an opportunity attack" benefit.

[cutlery]

Do you disagree? Are 4-on-1 fights ubiquitous in your games?

I suppose it depends on the table. One game I play in regularly skews heavily towards one or two big bads in most fights; the other in favor of swarms. The swarms tend to get the jump on the party, though, so we are quickly overrun. I'm not saying an occasional Mobile relocation isn't going to happen, but it might take more than one attack to get to a baddie that really would have no other targets after I left. A cunning action disengage can do the trick, but convincing them to trigger isn't so easy.

A misty step, on the other hand, can do the trick, but at a high cost. Create Bonfire is more reliable way to force movement, although it requires to use of a reaction to apply damage.

We also frequently have humanoids with gear as enemies, and a javelin or two seems to be rather standard issue.

Now, when it's me running things, I tend to move away from low intelligence enemies rather quickly, and they have ranged options. I won't say it never works, but 50% is a gross overestimate.

[MaxWilson]

Now, when it's me running things, I tend to move away from low intelligence enemies rather quickly, and they have ranged options. I won't say it never works, but 50% is a gross overestimate.

What kinds of monsters do you typically use? Saying "ranged options" doesn't tell me much, e.g. Giants have ranged options, but like most MM monsters their ranged damage is meagre compared to their melee damage, so a giant who opts to stand still instead of taking Booming Blade damage is giving up quite a lot of damage. For a Fire Giant (for example) it's the difference between 12d6+14 (56) and 4d10+7 (29).

Would an 11th level party at your table be likely to be fighting four Fire Giants, or one Fire Giant, or a Glabrezu (magical ranged option) and a Drow Mage (magical ranged attacks), or twelve quicklings (thrown daggers), or something else? Booming Blade would be good against the giants and the Glabrezu, and maybe the Quicklings; bad against the Drow Mage or an Orthon.

[CMCC]

I'd think 0% would be a safer assumption, in the case of BB. Bonus damage is a happy surprise, but you can't count on it, particularly with intelligent enemies.

GFB gets applied just as often as horde breaker is useful; I don't think 50% is quite reasonable for that, either.

GFB gets applied 100%. There’s never a reason to use it unless you have two enemies in adjacent squares. When applicable that beats 2 attacks almost every time - unless you have a +4 weapon or something.

Assuming that this is meant to be a comparison with Extra Attack classes, it's only favourable to Booming Blade if you are prioritising something other than damage.

At 5th level:

Dueling: 2d8+12= 21 damage

TWF: 3d6+12= 22.5

Then you get into other comparisons, like using a larger weapon, two handing a versatile weapon, Hunter's Mark, Rage damage. If an Extra attack class is only doing 2d8+Mod then they likely don't care about damage to begin with.

I’m comparing 2 attacks to 1 attack (all else equal). I’m not sure why you’re adding other factors in like a comparison between two classes or fighting styles. There are many ways to make 2 attacks better than 1 booming blade - you’ve identified a couple.

[Dork_Forge]

Even if a Cavalier "doesn't care" about damage because he's mostly about tanking, and is happy to do 3x d8+3 (22.5) with his Strength 16, it's still pretty sad for the Cavalier if a Mobile Necromancer 10/Life Cleric 1 is doing d6+5d8+2 (28) with Strength 15 and Booming Blade. Minimal investment by a Fighter still ought to result in more damage than minimal investment by a wizard.

Conceptually I think Booming Blade is great for EKs, but I hate how it interacts with 5E's spellcasting and multiclassing rules. My own personal solution isn't to nerf Booming Blade per se though, I just re-impose AD&D-style penalties for spellcasting in melee. That is, being incapacitated or casting a spell (unless you have Warcaster) allows enemies within range to make an opportunity attack. Warcaster's avoiding that opportunity attack replaces Warcaster's "cast a spell as an opportunity attack" benefit.

This situation seems a little extreme but I'd argue that the Wizard has made a larger investment that the Fighter by taking the cantrip.

Really though I find this situation intentionally extreme to a near comical degree, a Fighter with a 16 attacking stat after 3 ASIs, but not taking any feats or fighting styles for damage. You could even argue that the additional attacks granted by Unwavering Mark and Hold the Line should be factored into the damage consideration here.

I like the diea of adding reaction attacks to casting in melee though, that would add a substantial balancing factor to casting.

[MaxWilson]

This situation seems a little extreme but I'd argue that the Wizard has made a larger investment that the Fighter by taking the cantrip.

Really? I'm not seeing it. It's just a cantrip. What made it such a large investment?

Really though I find this situation intentionally extreme to a near comical degree, a Fighter with a 16 attacking stat after 3 ASIs, but not taking any feats or fighting styles for damage. You could even argue that the additional attacks granted by Unwavering Mark and Hold the Line should be factored into the damage consideration here.

Let's say you've got a Cavalier who started off with Str 14 (low die rolls or something), because Cavaliers still contribute in combat even without extreme DPR. Defense style helps him tank, and Defensive Duelist helps him stay alive, so take that as his human feat. He spends an ASI on Str 16, then another ASI on Lucky, and another on Healer. He's made minimal investments in damage (just an ASI), but it's still more investment than the Wizard made by spending a cantrip, and the wizard is still out-damaging him.

The wizard did invest significantly in mobility (Str 15 and Mobile), and mobility is good, but it would still be good even if Booming Blade didn't exist.

I saw wizards like this fairly frequently before my houserule. Now less so, because Warcaster is a moderately pricey investment for a wizard.

[Dork_Forge]

Really? I'm not seeing it. It's just a cantrip. What made it such a large investment?

They get five cantrips known by level ten, they invested one in Booming Blade vs the Figher that seems to have made no class based choice in favour of damage (presumably the Wizard would have taken BB at Wiz 1 though).

Let's say you've got a Cavalier who started off with Str 14 (low die rolls or something), because Cavaliers still contribute in combat even without extreme DPR. Defense style helps him tank, and Defensive Duelist helps him stay alive, so take that as his human feat. He spends an ASI on Str 16, then another ASI on Lucky, and another on Healer. He's made minimal investments in damage (just an ASI), but it's still more investment than the Wizard made by spending a cantrip, and the wizard is still out-damaging him.

The wizard did invest significantly in mobility (Str 15 and Mobile), and mobility is good, but it would still be good even if Booming Blade didn't exist.

I saw wizards like this fairly frequently before my houserule. Now less so, because Warcaster is a moderately pricey investment for a wizard.

You're now creating the parameters around the scenario, you originally just presented attacking stat and class, you are now adding in that the Fighter started with an abyssmal primary stat and invested an ASI whilst the Wizard chose Mobile. What's to say that the Wizard didn't use an ASI to raise their Str? After all a necromancer/Cleric has a lower dependency on Int and they still got two ASIs.

I think Wizards in general could use a nerf, but I don't think any of my players would accept it *shrug*

[MaxWilson]

They get five cantrips known by level ten, they invested one in Booming Blade vs the Figher that seems to have made (A) no class based choice in favour of damage (presumably the Wizard would have taken BB at Wiz 1 though).

(B) You're now creating the parameters around the scenario, you originally just presented attacking stat and class, you are now adding in that the Fighter started with an abyssmal primary stat and invested an ASI whilst the Wizard chose Mobile. What's to say that the Wizard didn't use an ASI to raise their Str? After all a necromancer/Cleric has a lower dependency on Int and they still got two ASIs.

I think Wizards in general could use a nerf, but I don't think any of my players would accept it *shrug*

(A) Since when does dedicating 11 levels to Fighter not count as a class-based choice? That's a HUGE investment.

(B) Str 14 isn't abyssmal, it's a moderately bad roll but nothing unusual. You already knew we were discussing "minimal investment" scenarios and a Fighter who's got Str 16--AFAIC I'm elaborating on the scenario we were already discussing.

Let's say the Wizard doesn't spend anything on Str. (Some of them don't.) Let's say he's just a very-standard Str 8 cleric/wizard with heavy armor proficiency. Mobile is still a good idea in this case in order to mitigate the 10' speed penalty for plate armor. You can of course invest in Dex 14 instead and then wear half-plate, and then arguably you don't need Mobile, but you know what we're not talking about? Booming Blade. Mobile isn't an investment in Booming Blade--rather, improved Booming Blade damage is a fringe benefit of investing in mobility, which is a common and good way IME to invest in survivability.

I've found that even with the effective nerf to Booming Blade, armored wizards are still popular. They don't need better-than-Fighter damage like the RAW gives them.

[Dork_Forge]

(A) Since when does dedicating 11 levels to Fighter not count as a class-based choice? That's a HUGE investment.

That is not the same line of discussion, we are talking about the investment for melee damage a Fighter vs a Wizard/Cleric has made, I personally don't consider 'being a Fighter' to begin with an investment in the framing of the question. If it was instead about achieving a certain amount of damage and the two builds were aiming for that then sure, but they aren't. In fact the Fighter has done well to be as bad at melee as they are here.

(B) Str 14 isn't abyssmal, it's a moderately bad roll but nothing unusual. You already knew we were discussing "minimal investment" scenarios and a Fighter who's got Str 16--AFAIC I'm elaborating on the scenario we were already discussing.

A starting Str of 14 after your racial bump is abyssmal, it is the primary stat of the character, their future subclass will have resources that key off of it and there's no good reason for it too be that low unless they've rolled a near cripplingly mediocre array. You can argue the character is not a primary damage contributer, they're a tank after all, except that to mark a creature you need to hit them. To top that off the mark lasts a turn, so you need to be reliably hitting things to do your job, despite the appearance of investing in tanking, by not raising Str they've made themselves severely handicapped.

And whilst you technically are elaborating on the scenario, this information could have shaped things differently were it available before hand. You clearly had specific things in mind, but I definitely didn't assume the Wizard had Mobile etc.

Let's say the Wizard doesn't spend anything on Str. (Some of them don't.) Let's say he's just a very-standard Str 8 cleric/wizard with heavy armor proficiency. Mobile is still a good idea in this case in order to mitigate the 10' speed penalty for plate armor. You can of course invest in Dex 14 instead and then wear half-plate, and then arguably you don't need Mobile, but you know what we're not talking about? Booming Blade. Mobile isn't an investment in Booming Blade--rather, improved Booming Blade damage is a fringe benefit of investing in mobility, which is a common and good way IME to invest in survivability.

Yes, Mobile is a good feat, I may be a bit dense but I'm not sure what point you're trying to get across here.

I've found that even with the effective nerf to Booming Blade, armored wizards are still popular. They don't need better-than-Fighter damage like the RAW gives them.

Still not agreeing that they have that better than Fighter damage RAW, the Wizard chose to make an in class choice to improve damage output, the Fighter is going out of their way to be below mediocre at damage in this scenario. Literally just taking Dueling instead of Defense would have pushed the Fighter back ahead and that's assuming that the Wizard is actually proc'ing the rider damage.

For the record whenever I use a SCAGtrip in a build or discuss them I never assume the rider in damage, at all. It's too niche to be meaningful to talk about to me, it assumes monsters are stupid enough to consistently hurt themselves/don't have a ranged option/someone else to hit etc. I also don't think that SCAGtrips just bridge the gap on their own, because they don't unless the comparison point is performing below expectations.

[CMCC]

To bring things back around... can you twin BB still?

Edit: Nope. “Doesn’t have a range of self”.

[cutlery]

I also don't think that SCAGtrips just bridge the gap on their own, because they don't unless the comparison point is performing below expectations.

I think that’s right. It isn’t a SCAGtrip that will make the new bladesinger mildly bonkers, it’s a SCAGtrip combined with their new special extra attack and song of victory.

What’s weird to me is these are in the same book (though the final piece that really puts it over the top, Shadow Blade, isn’t), so they should have figured that.

(1d8+10)*2 +3d8 is pretty nuts for someone who also gets full caster progression and the wizard list.

[Gtdead]

I'd rather use the old bladesinger and have two bladesongs per short rest than BB on extra attack. Freaking tasha's destroying my favorite subclass. :/

[MaxWilson]

A starting Str of 14 after your racial bump is abyssmal, it is the primary stat of the character, their future subclass will have resources that key off of it and there's no good reason for it too be that low unless they've rolled a near cripplingly mediocre array.

Mediocre arrays are neither crippling nor uncommon. 13, 10, 13, 9, 12, 12 isn't fantastic but it's well above the human norm, and it works perfectly fine in a number of roles including tanking. It's pretty sad however if it winds up doing better melee damage for less investment as a Booming Blade wizard than as a Cavalier Fighter, since tanking and Extra Attack(s) are the ONLY things the Cavalier class is built around while Booming Blade is only an afterthought for a wizard.

I feel like we already had this conversation, wonder why. The only thing we've learned is that you consider 14-15 a cripplingly bad Str for a human Fighter, and I don't. But you haven't even shown that that's relevant, because even with a Str of 18 (i.e. standard array or more ASIs devoted to Str/damage) the Booming Blade damage is still comparable to the Cavalier's damage and the Cavalier is still sad. Minimal Wizard investment in melee should not outdamage minimal Fighter investment in melee, because investing 11 levels in acquiring Extra Attack 2 is already a large investment compared to picking up a cantrip and the Mobile feat.

[Zhorn]

huh, linked page in the OP is now restricted

Product Preview Not Available
Unauthorized access is prohibited.

Does anyone still have access to see if there were changes being made, or know why the sudden viewing restriction?

[Dork_Forge]

Mediocre arrays are neither crippling nor uncommon. 13, 10, 13, 9, 12, 12 isn't fantastic but it's well above the human norm, and it works perfectly fine in a number of roles including tanking. It's pretty sad however if it winds up doing better melee damage for less investment as a Booming Blade wizard than as a Cavalier Fighter, since tanking and Extra Attack(s) are the ONLY things the Cavalier class is built around while Booming Blade is only an afterthought for a wizard.

Adventurers aren't the norm and whilst a lower stat array can be workable, a Cavalier Fighter functions on the basis of reliably hitting things. A Str 16 at 11th level is substantially worse at tanking than just having an 18 Str since their main tanking ability requires hitting a lot.

And the afterthought damage you're finding sad requires 1) a successful hit (requiring more and more luck the less the Wizard puts into whatever attack stat) and 2) The target to willingly move after the hit but before the rider expires. It's not as simple as 'as an after thought the Wizard melees harder than this 'low investment' Fighter,' things actually have to line up for that to be the case and in my experience and opinion the rider is so inconsistent that it isn't worth talking about outside of white rooms really.

I feel like we already had this conversation, wonder why. The only thing we've learned is that you consider 14-15 a cripplingly bad Str for a human Fighter, and I don't. But you haven't even shown that that's relevant, because even with a Str of 18 (i.e. standard array or more ASIs devoted to Str/damage) the Booming Blade damage is still comparable to the Cavalier's damage and the Cavalier is still sad. Minimal Wizard investment in melee should not outdamage minimal Fighter investment in melee, because investing 11 levels in acquiring Extra Attack 2 is already a large investment compared to picking up a cantrip and the Mobile feat.

Again it's not just about damage in the situation you've chosen, the lower the Strength the less the Cavalier is getting out of their subclass in many ways:

-The reliability they can actually mark a creature
-The number of mark attacks they can make
-The chance of hitting and subsequent damage of said mark attacks

The example Fighter has chosen to be harder to hit, which makes no benefit to anyone but their own self preservation if the enemy isn't inclined to hit them (incredibly high AC, but very poor provocation).

You seem to be equating the Mobile feat to auto triggering rider damage, if it was that simple then Swashbucklers would be top of the list to benefit there. It isn't that simple though, unless you're in a circumstance that favours it like the only person going into melee being the Wizard and the creature being stupid enough to fall for hurting itself instead of say, waiting a turn dodging or readying an attack.

For the Fighter to come off worse here you literally have to hand them a bad build whilst things turn up aces for the Wizard, despite the odds being against them. I already said that just taking Dueling overcomes those aces.

How does the DPR look if you actually factor in the to hit chances instead of just the averages and don't just assume rider success? I'm going to take a wild guess and say that the Wizard falls behind.

[MaxWilson]

For the Fighter to come off worse here you literally have to hand them a bad build whilst things turn up aces for the Wizard, despite the odds being against them. I already said that just taking Dueling overcomes those aces.

And I already said it's still comparable even if you have the Cavalier increase their investment in damage even more, e.g. with Dueling instead of Defense. (IMO a mistake because this Cavalier is primarily a tank.)

How does the DPR look if you actually factor in the to hit chances instead of just the averages and don't just assume rider success? I'm going to take a wild guess and say that the Wizard falls behind.

Still comparable.

[Dork_Forge]

And I already said it's still comparable even if you have the Cavalier increase their investment in damage even more, e.g. with Dueling instead of Defense. (IMO a mistake because this Cavalier is primarily a tank.)



Still comparable.

Okay... how large does the gap need to be for it to be acceptable to you?

I still think the assuming the rider is the issue, if you don't assume that damage it becomes much more reasonable...

[MaxWilson]

Okay... how large does the gap need to be for it to be acceptable to you?

There needs to be an interesting tradeoff, a distinct downside. Purely numerical gaps aren't as interesting.

Spoiler: Answering the numerical question anyway for completeness

Show

If you make me pick a purely numerical gap I'll have to say "the ideal gap between the melee damage of a Fighter and the melee damage of an unspecialized wizard would be the difference between a Fighter attacking N times, and a wizard plinking away with a sling", but I could live with letting the wizard do PHB cantrip damage instead, which tends to be about 50-65% the damage of the unspecialized Fighter.

From a gameplay standpoint though, I like the gap to be about safety, which fits better with the fighter vs. wizard tradeoff. Fighters are supposed to be safer than wizards. Wizards are supposed to be fragile. Therefore, I like the results when the Booming Blade wizard can pretty much close the numerical damage gap with a minimally-invested Fighter, at the cost of taking a melee opportunity attack (if he doesn't have Warcaster). This rule isn't just a solution to the SCAG cantrip problem (it also fixes annoying things about Warcaster, and 5E spellcasting in general), but the fact that it provides an answer to the "why even play a Fighter then?" question is a definite plus.

[bendking]

You have to make an assumption about the rider. I use the treantmonk number of 50%.

So at 5th level:
2 attacks 2d8+8 = 17 damage
1 booming (2d8+4) + (2d8 * 0.5) = 17.5 damage

That's not a fair comparison at all.
1. You have to calculate hit chance into the math here.
2. You're assuming the full-caster invests into STR/DEX as much as the martial does, which is a bad idea for the caster since he wants to invest in his casting stat.
3. Your assumption of 50% is quite generous unless you have some way to disengage for free/BA like Mobile or Cunning Action, AND the enemy isn't already locked in melee with another ally. I would say it's 25% at most barring Mobile/Cunning Action.
4. Every class with Extra Attack has more modifiers boosting their damage. For example, Barbarians have Rage and Reckless Attack, Battlemasters have maneuvers, Paladin's have Smite, etc.
5. You used a highly un-optimized martial in your example. You didn't use any of the best martial feats: PAM, GWM, CBE, Sharpshooter... I'll show some numbers for standard decent builds here.

Let's make a fairer comparison, using LudicSavant's DPR calculator. I'll use a Variant Human Wizard for your case (to get Mobile) compared to other standard martial builds. Here are his stats: 8 / 16 / 14 / 16 / 10 / 8.
I'll also give your Wizard a 50% chance to activate Booming Blade because he has Mobile.

A few caveats:
1. Keep in mind, we're talking about a Sorcerer/Wizard having Booming Blade as a bonus thing they can do, but not optimizing for melee damage beyond getting his DEX to 16, because that would (most likely) come at the expense of optimizing his full-casting, while martials heavily optimize for melee damage, because what else are they going to optimize for? However, I encourage you to show me a build for a Wizard (or any other full-caster with a single attack) that is on par with some of the DPR I'm going to show here.
2. I'm not even going to use some of the resources these classes can expend, although of course, that would come into play and push their numbers (a lot) further. This means I'm not using Rage on the Barbarian, Smite on the Paladin, or Action Surge on the Fighter.
3. Also, I'm not even using sub-classes here, which on martial classes usually boost their martial power further, whilst caster sub-class features usually boost your casting, not melee power, thus widening the gap even further (example: Vengeance's Vow of Enmity, Zealot's Divine Strike, Battlemaster's Maneuvers).

Overall, I tried to be as fair as possible towards the case you're making, perhaps a little too fair by not using class resources and sub-class features.
All the numbers are against an AC of 15.

The builds:
Sorcerer (Mobile)
Paladin (Dueling, PAM (Spear))
Paladin (GWF, PAM, GWM)
Barbarian Zealot (PAM, GWM)
Fighter (CBE, Sharpshooter)

(Why did I include two Paladins? To show the damage of a Paladin that isn't highly optimized for damage, and one that is)

5th level
Sorcerer (Mobile): 9.7
Paladin (Dueling, PAM): 15.17
Paladin (GWF, PAM, GWM): 19.89
Barbarian (PAM, GWM, Reckless): 31.65
Fighter (Archery, CBE, Sharpshooter): 22.8

11th level
Sorcerer (Mobile): 14.75
Paladin (Dueling, PAM, Improved Divine Smite): 31.15
Paladin (GWF, PAM, GWM, Improved Divine Smite): 39.74
Barbarian (PAM, GWM, Reckless): 40
Fighter (Archery, CBE, Sharpshooter): 39.2

As you can see, Booming Blade is nowhere near the DPR of actual good martial builds.
I'll accept any notes regarding the Wizard build as long as they keep INT high, and I'll happily edit this post with whatever improvements you have. I doubt whatever changes you propose will be able to compete with the other classes' DPR, but you're welcome to give it a try.

[Hael]

I'd rather use the old bladesinger and have two bladesongs per short rest than BB on extra attack. Freaking tasha's destroying my favorite subclass. :/

It’s a pretty strange compromise. It’s a decent buff to their melee skill, that gives them maybe an extra two or three lvls of martial viability. So let’s say you decide to be a backliner somewhere around lvl10 (from memory that’s when I started viewing melee as suboptimal). Now it probably feels ok till lvl 12. On the other hand the primary perk of the class is severely limited and the class will feel even more terrible for late tier 3-4 relative to other mages.

Again I question the design choice and what they were trying to accomplish.

[Dork_Forge]

There needs to be an interesting tradeoff, a distinct downside. Purely numerical gaps aren't as interesting.

Spoiler: Answering the numerical question anyway for completeness

Show

If you make me pick a purely numerical gap I'll have to say "the ideal gap between the melee damage of a Fighter and the melee damage of an unspecialized wizard would be the difference between a Fighter attacking N times, and a wizard plinking away with a sling", but I could live with letting the wizard do PHB cantrip damage instead, which tends to be about 50-65% the damage of the unspecialized Fighter.

From a gameplay standpoint though, I like the gap to be about safety, which fits better with the fighter vs. wizard tradeoff. Fighters are supposed to be safer than wizards. Wizards are supposed to be fragile. Therefore, I like the results when the Booming Blade wizard can pretty much close the numerical damage gap with a minimally-invested Fighter, at the cost of taking a melee opportunity attack (if he doesn't have Warcaster). This rule isn't just a solution to the SCAG cantrip problem (it also fixes annoying things about Warcaster, and 5E spellcasting in general), but the fact that it provides an answer to the "why even play a Fighter then?" question is a definite plus.

This makes me think that the game would be served by adding in a class stipulation that you can't cast in armor unless you gain an ability that specifically over rides it. This would allow armored subclasses to exist but effectively locks the Wizard out of grabbing armor on a dip, I think this would be a less simple but more effective fix. After all an opportunity attack can be nasty, but if the Wizard is in armor then chances are a reaction cast of Shield would shoot their AC into the 20s.

[cutlery]

Don't forget your party can also encourage the enemy to trigger the effect as well, for example Flame Sphere, create bonfire or some other effect like that might make an enemy want to move and trigger the Booming blade.

Sure, but that's often relatively low on the list of priorities; it's just 2d8 damage at 5th, after all - a nice bonus, but there are fireballs and hungers of hadar flying around, or the sticky barbarian in range. It isn't worth the party reshaping their formation around it. It might be worth applying movement effects; but if the Warlock with repelling blast "helps" in this way, as often as not they kill the target before the rider has a chance to trigger.

Also: much of the internet still thinks things like standing from prone or forced movement effects trigger it. It seems likely to me those misrulings play into the estimate of 50%.

What kinds of monsters do you typically use?

Humanoids are by far the most common. Smart undead, Illithid, and other creatures later. Demons and Devils too; but again the smart ones.

Anyway, regardless of what our respective tables look like - telling people that they will have a 50% chance of triggering the rider on BB is bad advice.

Better to talk instead about the guaranteed damage from a hit, and the pleasant bonus of the rider when it applies than to use figures like 50% and set expectations too high.

One can easily say the cantrip adds 0/1d8/2d8/4d8 damage with a rider and leave the rider for the tactical discussion and not part of the guaranteed damage analysis (which is appropriate, because it is not guaranteed).

[Sol0botmate]

I don't see the problem? Just ignore it if you don't like it?

XGTE is still official book, same as Tasha's. Both versions are valid.

[Tanarii]

This makes me think that the game would be served by adding in a class stipulation that you can't cast in armor unless you gain an ability that specifically over rides it. This would allow armored subclasses to exist but effectively locks the Wizard out of grabbing armor on a dip, I think this would be a less simple but more effective fix. After all an opportunity attack can be nasty, but if the Wizard is in armor then chances are a reaction cast of Shield would shoot their AC into the 20s.

It would definitely have to be a special (negative) feature of Wizard and Sorcerer spellcasting class features. Because all other spell casters natively start with armor, including warlocks and bards as Arcane casters,

OTOH we all know how well a negative restrictions went over with Druids and Necromancy in 5e, and Paladins historically. And Races. Not to mention spell casting itself.

[Zhorn]

I don't see the problem? Just ignore it if you don't like it?

XGTE is still official book, same as Tasha's. Both versions are valid.

SCAG not XGtE, and if rumours are true we can expect an errata to the old versions.
Yes it can be ignored for home games, but organised play will require the latest versions, and online directories will also be updated to match the latest version.

[CMCC]

That's not a fair comparison at all.
1. You have to calculate hit chance into the math here.
2. You're assuming the full-caster invests into STR/DEX as much as the martial does, which is a bad idea for the caster since he wants to invest in his casting stat.
3. Your assumption of 50% is quite generous unless you have some way to disengage for free/BA like Mobile or Cunning Action, AND the enemy isn't already locked in melee with another ally. I would say it's 25% at most barring Mobile/Cunning Action.
4. Every class with Extra Attack has more modifiers boosting their damage. For example, Barbarians have Rage and Reckless Attack, Battlemasters have maneuvers, Paladin's have Smite, etc.
5. You used a highly un-optimized martial in your example. You didn't use any of the best martial feats: PAM, GWM, CBE, Sharpshooter... I'll show some numbers for standard decent builds here.
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Again, you’re comparing between classes for some reason. I’m not sure why. The question is whether you would make a single booming attack or 2 attacks with the same character (all else equal).

You’re over complicating the analysis here.

And you don’t HAVE to calculate hit chance, but you can - that does provide an important additional layer of data.

Unfortunately, that doesn’t change the result. Booming remains about 0.5 dpr better than 2 attacks from 0 AC through 25 AC. At 0 it’s 0.46 and at 25 the difference drops to about 0.3

The difference evens out at a +5 damage mod. And turns in favor of two attacks at +6. At level 11 it swings back to BB quite a bit unless you have 3 attacks.

If you want to discuss booming blade builds vs extra attack builds that is (should be) a separate discussion that I’m not particularly interested in having.

[KorvinStarmast]

Don't forget your party can also encourage the enemy to trigger the effect as well, for example Flame Sphere, create bonfire or some other effect like that might make an enemy want to move and trigger the Booming blade.

Fear or turn undead (for undead) will likewise trigger it, and an OA...

[bendking]

Again, you’re comparing between classes for some reason. I’m not sure why. The question is whether you would make a single booming attack or 2 attacks with the same character (all else equal).

You’re over complicating the analysis here.

And you don’t HAVE to calculate hit chance, but you can - that does provide an important additional layer of data.

Unfortunately, that doesn’t change the result. Booming remains about 0.5 dpr better than 2 attacks from 0 AC through 25 AC. At 0 it’s 0.46 and at 25 the difference drops to about 0.3

The difference evens out at a +5 damage mod. And turns in favor of two attacks at +6. At level 11 it swings back to BB quite a bit unless you have 3 attacks.

If you want to discuss booming blade builds vs extra attack builds that is (should be) a separate discussion that I’m not particularly interested in having.

Emphasis mine.
It seems you did not understand my point. Booming Blade does NOT have 0.5 DPR advantage because you are doing this comparison on a highly unoptimized martial that has no apparent modifiers on their attack besides their ability modifier, which is not a fair comparison to make since most martial have quite a bit of modifiers going on (CBE, SS, PAM, GWM).
Just to put a nail in this coffin, I'll provide you with the numbers for using Booming Blade with these builds (even though they don't have access to it), just like you're asking, at 11th level, which as you said yourself is favorable for Booming Blade:

Extra Attack
Paladin (GWF, PAM, GWM, Improved Divine Smite): 39.74
Barbarian (PAM, GWM, Reckless): 40

Booming Blade (50% chance)
Paladin (GWF, PAM, GWM, Improved Divine Smite): 36
Barbarian (PAM, GWM, Reckless): 32.6

Booming Blade (10% chance)
Paladin (GWF, PAM, GWM, Improved Divine Smite): 32
Barbarian (PAM, GWM, Reckless): 30.5

Keep in mind that the 50% activation chance on the rider is very generous since these classes have no way of disengaging without using their action.
They should rightfully have more of a 10% activation chance or lower, since the only way it's going to activate is if the enemy they're locked in melee with has no qualms triggering an AoO.

Now, I've clearly shown you that the DPR with Booming Blade is significantly lower than Extra Attack, as is to be expected.
You're welcome to show me math that proves otherwise, but I'd like to see you approach my actual argument, which is, again, that martial don't use Extra Attack in the box, they have a bunch of class features, sub-class features, and feats that boost their melee, thus making Extra Attack much more worthwhile than Booming Blade due to the multiplication of modifiers.