Can Lucky replace Resilient (CON)/War Caster?

[meandean]

I'm guessing the basic answer to my question is "it depends on how combats in your game tend to go", but I wanted to know what factors folks would figure into the calculation.

I have a level 10 lore bard/level 1 life cleric. I rolled well on abilities, so I've only have had to use one ASI towards maxing my CHA. I used the level 8 ASI on Ritual Caster (Wizard). I have odd numbers in CON (15) and WIS (13). So, Resilient (CON) would be a pretty obvious feat to take, and Fey Touched would be good to round out my WIS and give me misty step. I also like Inspiring Leader a lot. And I won't get into the details, but our DM has homebrewed some tempting feats. Yet, I've always heard that Lucky is a super-powerful, banned-at-many-tables, must-have feat.

So, basically I have a bunch of feat options, but I can only fit in three of them. My question is, is it plausible to rely on Lucky to both undo any bad concentration saves, and perhaps serve other useful functions? Then I could take both Inspiring Leader and Fey Touched, or however else I want to do it.

I imagine I get targeted an average amount for a backliner. I mostly do battlefield control, so unintelligent enemies don't go after me much, but intelligent enemies often do. The life cleric dip helps my AC (18) by giving me a breastplate (I don't have the STR for heavy armor) and a shield. I use find greater steed to ride a pegasus, so I'm pretty maneuverable. But, naturally, I'm not exactly unhittable.

Thanks so much for any help!!

[lall]

If you want to be super awesome at maintaining concentration, go Resilient. It just depends on your priorities. Lucky would help with ability checks and you are a bard.

[RogueJK]

I'd say no. Resilient is a flat scaling boost to all Concentration checks (plus all other CON saves). Warcaster is Advantage all the time on Concentration. Lucky is basically Advantage 3 times per day (or less if you use some of your Luck points for something else).

As a primary caster, you're almost certainly going to want the bonus to Concentration more than 1/2/3 times per day. And if you're worried about saving your Luck points for future important Concentration rolls, you're going to be less likely to spend them on all the other stuff, so they may frequently end up being unused at the end of the day.

[ATHATH]

As a primary caster, you're almost certainly going to want the bonus to Concentration more than 1/2/3 times per day.
Eh, it really depends on how close to the front line you plan to be and if your DM tends to target/focus down casters, especially since the OP is going to be flying around on a pegasus. Also, the ability to reroll important rolls (Deception checks, Insight checks, saving throws, a BBEG's spell attack roll that just crit, etc.) can really save you from some "oh no" moments. Of course, Lucky isn't guaranteed to save you from all of those situations, as you can still roll poorly on your extra roll, but if your failure in the first place required a poor roll, your odds of being saved by using Lucky on that failed roll are pretty good.

It's not as mandatory as the OP implies it is and it's not generally seen as a ban-worthy feat, but it's very nice to have and can save your bacon in a lot of situations.

[MaxWilson]

Yet, I've always heard that Lucky is a super-powerful, banned-at-many-tables, must-have feat.

That is wildly overselling Lucky. It's a nice versatile feat that is almost never useless, but not particularly powerful. It's a good default feat to pick when you've already got everything you really wanted. It's also a pretty good defensive feat that's often better than Tough in terms of extra effective HP per day (from negated hits or crits), while still giving you the option of converting those phantom quasi-HP into higher initiative rolls or concentration saves.

In your specific case, taking Lucky as a form of poor man's Warcaster that gives more out of combat benefits is not a terrible idea. I think you could get away with it, especially if you still take Resilient (Con), since failed Concentration saves should already be rare (and this also gives you more protection against other things that can break your concentration, such a paralysis).

But if you're expecting Lucky to be anything more than a little extra insurance against unlucky failures... it's not.

[ATHATH]

Do you have a +1 to saves from anywhere? If you do, definitely take Resilient(CON), because that'll boost your base CON save to +8 (without the aforementioned +1 to saves). If you can get that +1 to saves from somewhere, you'll be physically unable to fail concentration saves from hits that deal <=21 damage (unless you're debuffed somehow), which is a game-changer.

[LudicSavant]

Potentially! It really depends on how many Concentration checks you're failing.

Not making. Failing. Remember, Lucky lets you reroll after seeing the roll, which is mathematically far better than "Advantage on 3 checks a day."

It also depends on how much you're benefitting from the other aspects of the feats (such as the OA from Warcaster, or the benefit to normal Constitution saves from Resilient).


Lucky is basically Advantage 3 times per day (or less if you use some of your Luck points for something else).

Lucky is actually quite a bit better than Advantage 3/day, since you can choose to reroll after seeing the roll.

[Gignere]

Potentially! It really depends on how many Concentration checks you're failing.

Not making. Failing. Remember, Lucky lets you reroll after seeing the roll, which is mathematically far better than "Advantage on 3 checks a day."

It also depends on how much you're benefitting from the other aspects of the feats (such as the OA from Warcaster, or the benefit to normal Constitution saves from Resilient).



Lucky is actually quite a bit better than Advantage 3/day, since you can choose to reroll after seeing the roll.

You can also turn disadvantage into super advantage with lucky 3x a day. It can lead to some hilarious role playing things like lying down to better save against a dragons breath or closing your eyes before making an attack roll.

[ATHATH]

You can also turn disadvantage into super advantage with lucky 3x a day. It can lead to some hilarious role playing things like lying down to better save against a dragons breath or closing your eyes before making an attack roll.
Use the Force, Luke!

[Deen]

Depends. If you are for example Paladin you are better maxing out CHA to 20 as fast as possible as with +5 to CON save you basically have RES (CON) like other classes that need to take feat. Only on level 17 they get +6, so that's a long way. I would then probably take Lucky over RES (CON) as it's more universal and can turn many tides in your favour, not just for concentration. I usually go 20 CHA, 1 level Divine Soul dip for Favoured by the Gods and Lucky. This way I have as good chance to remain CON as other classes but I can always use extra 2d4/short rest from Divine Soul to try to past that CON save and I have Lucky as back up.

However, for any other class that does not have CON prof but is a caster - I would take RES (CON) hands down. Warcaster only for specific builds over RES (CON) like sword n shield Sorcadins for example or Arcane Cleric etc.

[Segev]

You can also turn disadvantage into super advantage with lucky 3x a day. It can lead to some hilarious role playing things like lying down to better save against a dragons breath or closing your eyes before making an attack roll.

"I turn around and hurl the dart over my shoulder at the target behind me!"

[MrStabby]

There are ways other than Con saves to lose concentration on a spell. Anything that incapacitates you - hold person, banishment any stun effect... Lucky can help with all of these in a way that resilient might not.

Basically, read your campaign, your roles and the risks and make a decision based on YOUR game.

[Keravath]

Generally, I find Lucky to be a third tier feat - meaning I pick it after taking all the other useful feats because it MIGHT come in handy in a pinch for any character but doesn't really substitute for any of the better feats.

I have one character who took it early in their career and it was insignificant. Most of the re-rolls that I failed due to high DC, I failed anyway when re-rolling with Lucky. If I need to roll a 15 to succeed then there ia 70% chance of failure and if I fail the first time there is still a 70% chance of failure on the "Lucky" re-roll. The limitation of 3 re-rolls/day also means I tend to save it for important rolls so there are days that may pass without it being used at all.

I have never understood tables that ban it for being overpowered - the only way I can see that happening might be for tables that have one combat/long rest - can use all their long rest resources in a single combat or encounter - and thus can afford to use Lucky for anything. One character in a game I am DMing has the feat and it has proven as insignificant for that character as for my own. Just an occasional rare success that makes for some fun narration.

Another character I have is level 16 - 14 lore bard/2 hexblade warlock - they have resilient con and just picked up warcaster most recently. I may take Lucky at level 16 bard since he has already picked up the most useful feats and the best thing about Lucky is that it never hurts to have it even if it isn't that great most of the time.

So, depending on your character and their stats, I would rank resilient con, warcaster and fey-touched as all likely more useful than Lucky.

--------

However, if you NEVER find yourself needing to make more than 3 constitution saving throws in a day - or NEVER have more than 3 incidences when you might want to re-roll a d20 - then Lucky could be better for a particular character at a particular level.

Advantage is roughly the equivalent of +4 - +5 over a central range of die rolls (7-15) [only +5 if you need to roll an 11+ for success]. This means that when your proficiency is +4, for typical die rolls, advantage is about the same or has a slight edge while if your proficiency is +5 or more the flat bonus is strictly better. This means that if you almost never use Lucky and are never forced into situations where you would need it more than 3 times in a day, it could be better than resilient con (just from the perspective of making constitution saving throws - since your con is odd however, resilient con has the additional bonus of extra hit points).

Also, the advantage provided on concentration saves by warcaster can be compared similarly to both resilient con and Lucky. Warcaster is equivalent to Lucky for concentration saves but applies to every concentration save you make - if you make more than 3 a day then it is better than Lucky. However, warcaster doesn't apply to other constitution saving throws and won't increase hit points.

So there is an arguable niche for Lucky due to its flexibility and versatility - it could be used for a critical skill check as well as any save but the limit of 3 times day means that it is not as effective as resilient con (if you have more than 3x constitution saves of any kind in a day) or warcaster (if you have more than 3x concetration saves in a day) - or in any case, where you might have more than 3 die you need to re-roll in a day.

The longer the adventuring day at your table, the less useful Lucky is due to the increase in die rolls that the character makes that might benefit from a re-roll.

[Segev]

Generally, I find Lucky to be a third tier feat - meaning I pick it after taking all the other useful feats because it MIGHT come in handy in a pinch for any character but doesn't really substitute for any of the better feats.

I have one character who took it early in their career and it was insignificant. Most of the re-rolls that I failed due to high DC, I failed anyway when re-rolling with Lucky. If I need to roll a 15 to succeed then there ia 70% chance of failure and if I fail the first time there is still a 70% chance of failure on the "Lucky" re-roll. The limitation of 3 re-rolls/day also means I tend to save it for important rolls so there are days that may pass without it being used at all.

To me, Lucky is best used on a character who has very good success rates with skills. It's not there to turn likely-failures into maybe-successes. It's there to guard against those times when your Expertise With Advantage that should have worked ... didn't, just because even Advantage doesn't mean you can't roll a 2 and a 6 on the die when you needed at least an 8 to succeed. True, not even Lucky, with a third die to roll, guarantees you won't roll a 3 on the third one, but having that one more chance feels very good when it's likely to succeed.

If you use the Crawford-approved version of Lucky, it also takes that expertise-but-at-disadvantage roll you feel almost robbed of because you got a 20 and a 2 and had to take the 2 into a 20. Sure, you rolled a 10 on the luck die, but the big thing was getting to pick any of the three, so you KNEW that point would make it a success!

[Gignere]

To me, Lucky is best used on a character who has very good success rates with skills. It's not there to turn likely-failures into maybe-successes. It's there to guard against those times when your Expertise With Advantage that should have worked ... didn't, just because even Advantage doesn't mean you can't roll a 2 and a 6 on the die when you needed at least an 8 to succeed. True, not even Lucky, with a third die to roll, guarantees you won't roll a 3 on the third one, but having that one more chance feels very good when it's likely to succeed.

If you use the Crawford-approved version of Lucky, it also takes that expertise-but-at-disadvantage roll you feel almost robbed of because you got a 20 and a 2 and had to take the 2 into a 20. Sure, you rolled a 10 on the luck die, but the big thing was getting to pick any of the three, so you KNEW that point would make it a success!

It’s not just Crawford approved its the actual RAW for lucky. It lets you choose which d20 to use. So if you roll at advantage or disadvantage and before you know the result you can choose whichever die roll to use.

[Segev]

It’s not just Crawford approved its the actual RAW for lucky. It lets you choose which d20 to use. So if you roll at advantage or disadvantage and before you know the result you can choose whichever die roll to use.

Eh, I read the RAW as saying you replace ONE of the dice when you roll with (dis)advantage and spend the luck point. For Advantage, this changes nothing, but for Disadvantage, this means you (likely) are going to choose the lower of the two dice, and hope the new roll is higher than the higher die.

I can see the RAW being read either way, don't get me wrong. I can accept that, with Crawford's input, that the intent might've been to turn Disadvantage into Super Advantage. It IS a feat you've expended, and while I used to think it silly, it has since occurred to me that somebody who's cocky about his luck pulling such stunts is actually just a character archetype statement.

[Gignere]

Eh, I read the RAW as saying you replace ONE of the dice when you roll with (dis)advantage and spend the luck point. For Advantage, this changes nothing, but for Disadvantage, this means you (likely) are going to choose the lower of the two dice, and hope the new roll is higher than the higher die.

I can see the RAW being read either way, don't get me wrong. I can accept that, with Crawford's input, that the intent might've been to turn Disadvantage into Super Advantage. It IS a feat you've expended, and while I used to think it silly, it has since occurred to me that somebody who's cocky about his luck pulling such stunts is actually just a character archetype statement.

The RAW specifically said before the outcome is known to me that means both the extra advantage or disadvantage dice are still in play.

[Segev]

The RAW specifically said before the outcome is known to me that means both the extra advantage or disadvantage dice are still in play.

Just to make sure I'm quoting things accurately and not running off of a flawed memory, here is the relevant text from the feat: "Whenever you make an attack roll, an ability check, or a saving throw, you can spend one luck point to roll an additional d20. You can choose to spend one of your luck points after you roll the die, but before the outcome is determined. You choose which of the d20s is used for the attack roll, ability check, or saving throw."

The point where the two readings differ isn't the point about "outcome." It's the point about "after you roll the die."

There are actually three valid readings I can think of, though I admit one of them only occurred to me after I learned there were more than one and started analyzing it. I will outline them in the case of disadvantage, as that's where it's most interesting:

You roll the two dice for disadvantage, and see that at least one of the dice is low and predict it will result in failure. You spend a luck point to roll "an additional" d20, for a total of three, and now may choose any of the three as the result.
This turns disadvantage into "super advantage," which can either be really hokey or really cool.
You roll the two dice for disadvantage, and see that at least one of them is low enough that you predict it will result in a failure. You spend a point of luck to roll "an additional" d20 for the low one, and pick which of the two dice is the actual "second" die for the disadvantage roll. You then compare the final two dice and take the lower one.
This means that your higher die provides a "cap" to how good your roll can be even before you spend a luck point. If you roll better than the higher die on the luck die, you still are only replacing the low die with it, making the old "high die" the new "low die" for the final determination.
This is complicated enough to need an example. Say you roll with disadvantage and get a 2 and a 14. You choose to spend a luck point, and want to roll a luck die on the "2." You roll a 16. You choose that, and now your two dice are 16 and 14. Because you're rolling with disadvantage, you get the 14.
This version preserves the hardship of disadvantage, because your higher die is the BEST you can do even with a luck point.
You roll the two dice for disadvantage, and then the lower one becomes the die result. Before you know if that succeeds or fails, you determine that it's likely-enough to be a failure that you choose to spend a luck point. This lets you roll an additional d20, and choose between the low result you got from disadvantage and the new, lucky die.
This reading prevents "super advantage," but is more forgiving than the second reading because you CAN roll higher than even the high die from the disadvantaged roll.
This one interprets "making the check" as the full process of rolling both dice and taking the lower one, treating that as "one die" for purposes of the check. The Luck point then adds "an additional" die and you pick between the two.
I think it fair to say this third way is the most "middle of the road," in that it leaves Lucky able to save a bad Disadvantaged roll even when both dice were low, but it doesn't make it optimal to deliberately give yourself Disadvantage in order to convert it to Super Advantage.

Whether "super advantage" gained from disadvantage+Luck point is a good thing or a bad thing is subjective.

[Deen]

Just to make sure I'm quoting things accurately and not running off of a flawed memory, here is the relevant text from the feat: "Whenever you make an attack roll, an ability check, or a saving throw, you can spend one luck point to roll an additional d20. You can choose to spend one of your luck points after you roll the die, but before the outcome is determined. You choose which of the d20s is used for the attack roll, ability check, or saving throw."

The point where the two readings differ isn't the point about "outcome." It's the point about "after you roll the die."

There are actually three valid readings I can think of, though I admit one of them only occurred to me after I learned there were more than one and started analyzing it. I will outline them in the case of disadvantage, as that's where it's most interesting:

You roll the two dice for disadvantage, and see that at least one of the dice is low and predict it will result in failure. You spend a luck point to roll "an additional" d20, for a total of three, and now may choose any of the three as the result.
This turns disadvantage into "super advantage," which can either be really hokey or really cool.
You roll the two dice for disadvantage, and see that at least one of them is low enough that you predict it will result in a failure. You spend a point of luck to roll "an additional" d20 for the low one, and pick which of the two dice is the actual "second" die for the disadvantage roll. You then compare the final two dice and take the lower one.
This means that your higher die provides a "cap" to how good your roll can be even before you spend a luck point. If you roll better than the higher die on the luck die, you still are only replacing the low die with it, making the old "high die" the new "low die" for the final determination.
This is complicated enough to need an example. Say you roll with disadvantage and get a 2 and a 14. You choose to spend a luck point, and want to roll a luck die on the "2." You roll a 16. You choose that, and now your two dice are 16 and 14. Because you're rolling with disadvantage, you get the 14.
This version preserves the hardship of disadvantage, because your higher die is the BEST you can do even with a luck point.
You roll the two dice for disadvantage, and then the lower one becomes the die result. Before you know if that succeeds or fails, you determine that it's likely-enough to be a failure that you choose to spend a luck point. This lets you roll an additional d20, and choose between the low result you got from disadvantage and the new, lucky die.
This reading prevents "super advantage," but is more forgiving than the second reading because you CAN roll higher than even the high die from the disadvantaged roll.
This one interprets "making the check" as the full process of rolling both dice and taking the lower one, treating that as "one die" for purposes of the check. The Luck point then adds "an additional" die and you pick between the two.
I think it fair to say this third way is the most "middle of the road," in that it leaves Lucky able to save a bad Disadvantaged roll even when both dice were low, but it doesn't make it optimal to deliberately give yourself Disadvantage in order to convert it to Super Advantage.

Whether "super advantage" gained from disadvantage+Luck point is a good thing or a bad thing is subjective.

I think you read way too much into it. Quoting Feat itself it's very clear:

"roll an additional d20. You can use this ability after the original roll, but before the outcome is revealed. You choose which of the d20s is used for the attack roll, ability check, or saving throw."

1. It's ADDITIONAL dice, it does not replace anything.

2. You can use Lucky after you see rolls of your original roll

3. You chose WHICH of the "d20s" (it says "s" in desctiption) to use.

That's it. So yes, you can turn disadvantage into super advantage.

[MoiMagnus]

Yet, I've always heard that Lucky is a super-powerful, banned-at-many-tables, must-have feat.

That was indeed something I've seen in the early days of 5e forums, but the community seems to have moved past that. One of the reasons being that peoples realised that just taking +2 in your main ability score is also very strong, quite polyvalent, always useful, etc. At least that how it went at my table, the lucky feat was in almost every build up until the players realised that feats are not always strictly better than ASI and just because feats are allowed doesn't mean ASI are a bad choice.

But yeah, I've you're having 10min workdays and have only a handful of important checks per long rest, then Lucky is going to be very strong (and Bardic Inspirations will be OP).

[Chronos]

Nobody ever takes that interpretation to its logical conclusion, though. Suppose I roll a saving throw at disadvantage, and I don't like what I got, so I use a luck point. Now I roll another die, and then I can choose any die. OK, I choose the one the DM rolled last round. It's still sitting there on the table, with an 18 showing on top. It says "any", right?

That's obviously not the intent of Lucky, but you get there using the exact same reasoning that leads to super-advantage. Obviously, the reasoning is faulty.

And it's not even relevant, anyway, because the rules as written are clear. The general rules for advantage and disadvantage tell you how they interact with luck abilities. As happens so often, the Rules as Written disagree with the Rules as Crawford.



Back to the OP: One point not to forget about is that Resilient Con will also give you +1 to Con. Since you currently have an odd Con score, that'll increase your modifier. Which will both increase your Con save even further... and also increase your HP. Everyone likes having more HP.

[Eldariel]

Nowadays I generally take Lucky before Res: Con on backline casters. The key realisation that lead to this was that often with good mechanical play (go prone vs. ranged enemies, and use mobility, melee allies, control spells and if necessary summons to avoid melee enemies) you will not roll all that many Concentration checks of relevance even at the 6-8 encounter points. Irrelevant checks towards the end of encounter aren't really worth succeeding at unless you have some summon you want to keep for the next fight anyways.

To this end, on most days Lucky is a net positive between rerolling failed Concentration AND Initiative/Enemy crit/Counterspell/Dispel checks/high impact saves (and very occasionally key ability checks or attack rolls), while still providing War Caster levels of rerolling for when needed on Concentration. Not all days but generally you come out net positive compared to the other feats due to how many other ways you have to avoid damage and how often Concentration succeeds without effort (you sre over 50% basically always so you need to reroll under half of your Concentration checks let alone when cutting the low impact ones when the fight is basically won away).

Now, this only applies to ranged avoidy casters. It's very different for fighty casters (lots of damage instances that you actively desire since you want to tank = lots of Concentration rolls) and especially martial casters (War Caster giving OA spells is just insanely huge if you have even a moderate chance of getting OAs consistently - it totally breaks action economy to make any single target spell a reaction). But for ranged avoidy casters, the advantage of Lucky is generally significant. And even frontline casters generally do want Lucky down the line.

[MoiMagnus]

Nowadays I generally take Lucky before Res: Con on backline casters. The key realisation that lead to this was that often with good mechanical play (go prone vs. ranged enemies, and use mobility, melee allies, control spells and if necessary summons to avoid melee enemies) you will not roll all that many Concentration checks of relevance even at the 6-8 encounter points. Irrelevant checks towards the end of encounter aren't really worth succeeding at unless you have some summon you want to keep for the next fight anyways.

To this end, on most days Lucky is a net positive between rerolling failed Concentration AND Initiative/Enemy crit/Counterspell/Dispel checks/high impact saves (and very occasionally key ability checks or attack rolls), while still providing War Caster levels of rerolling for when needed on Concentration. Not all days but generally you come out net positive compared to the other feats due to how many other ways you have to avoid damage and how often Concentration succeeds without effort (you sre over 50% basically always so you need to reroll under half of your Concentration checks let alone when cutting the low impact ones when the fight is basically won away).

Now, this only applies to ranged avoidy casters. It's very different for fighty casters (lots of damage instances that you actively desire since you want to tank = lots of Concentration rolls) and especially martial casters (War Caster giving OA spells is just insanely huge if you have even a moderate chance of getting OAs consistently - it totally breaks action economy to make any single target spell a reaction). But for ranged avoidy casters, the advantage of Lucky is generally significant. And even frontline casters generally do want Lucky down the line.

I agree. Though the same argument can be pushed further by saying that for a ranged avoidy caster, increasing your Concentration capability might not even be worth a feat. So it's more "Res: Con is not worth it, but as a side effect of taking Lucky you can sometimes reroll once of the very few important concentration rolls you will have to do."

(Well, to be fair, I'm ignoring the additional HP from Res:Con here, which can be very handy in dire situations)

[Eldariel]

I agree. Though the same argument can be pushed further by saying that for a ranged avoidy caster, increasing your Concentration capability might not even be worth a feat. So it's more "Res: Con is not worth it, but as a side effect of taking Lucky you can sometimes reroll once of the very few important concentration rolls you will have to do."

(Well, to be fair, I'm ignoring the additional HP from Res:Con here, which can be very handy in dire situations)

I really like Lucky for rerolling the Counterspell/Dispel Int check.

[RSP]

Lucky’s a fine Feat, particularly good for negating opponents’ crit rolls, however, Res (Con) is the better feat for a caster (particularly if odd Con score).

My take on Conc checks is you want to get as close to auto pass on the DC 10 rolls as you can, as soon as you can. I’d much rather have that than a reroll or Adv (from Warcaster).

[Keravath]

Nowadays I generally take Lucky before Res: Con on backline casters. The key realisation that lead to this was that often with good mechanical play (go prone vs. ranged enemies, and use mobility, melee allies, control spells and if necessary summons to avoid melee enemies) you will not roll all that many Concentration checks of relevance even at the 6-8 encounter points. Irrelevant checks towards the end of encounter aren't really worth succeeding at unless you have some summon you want to keep for the next fight anyways.

To this end, on most days Lucky is a net positive between rerolling failed Concentration AND Initiative/Enemy crit/Counterspell/Dispel checks/high impact saves (and very occasionally key ability checks or attack rolls), while still providing War Caster levels of rerolling for when needed on Concentration. Not all days but generally you come out net positive compared to the other feats due to how many other ways you have to avoid damage and how often Concentration succeeds without effort (you sre over 50% basically always so you need to reroll under half of your Concentration checks let alone when cutting the low impact ones when the fight is basically won away).

Now, this only applies to ranged avoidy casters. It's very different for fighty casters (lots of damage instances that you actively desire since you want to tank = lots of Concentration rolls) and especially martial casters (War Caster giving OA spells is just insanely huge if you have even a moderate chance of getting OAs consistently - it totally breaks action economy to make any single target spell a reaction). But for ranged avoidy casters, the advantage of Lucky is generally significant. And even frontline casters generally do want Lucky down the line.

I think there is one more factor you haven't mentioned. The style of campaign you are playing. If you have a DM that runs the opponents and NPCs so that they go "duh, bad guy" run up and attack the nearest melee - then I could agree with you.

However, in many of the games I have played, being a caster often paints a big red targeting X on your head. For intelligent opponents, a caster is often the primary target, whether the caster is an arcane or a divine caster. Intelligent opponents realize that breaking concentration on the buff or harmful spell is often the most useful thing that they can do (or knocking out the healer to prevent yo-yo healing). Perhaps an opposing monk shadowsteps next to the caster and uses stun. Reslient con helps pass those multiple stun checks far more than Lucky when spread over an adventuring day.

Similarly, the backline caster is likely a primary target for enemy spellcasters and ranged attackers. Going prone may help but it again paints a target for any enemy melee within range - they should take an opportunity attack if it means attacking a prone enemy caster at advantage.

Anyway, if you play in a game where a DM has opponents ignore the backline then Lucky is likely the better choice - if your DM plays intelligent opponents with intelligence then the backline caster is far more lilkely to be a target than your scenario seems to assume. (at least in my experience).

[Eldariel]

I think there is one more factor you haven't mentioned. The style of campaign you are playing. If you have a DM that runs the opponents and NPCs so that they go "duh, bad guy" run up and attack the nearest melee - then I could agree with you.

However, in many of the games I have played, being a caster often paints a big red targeting X on your head. For intelligent opponents, a caster is often the primary target, whether the caster is an arcane or a divine caster. Intelligent opponents realize that breaking concentration on the buff or harmful spell is often the most useful thing that they can do (or knocking out the healer to prevent yo-yo healing). Perhaps an opposing monk shadowsteps next to the caster and uses stun. Reslient con helps pass those multiple stun checks far more than Lucky when spread over an adventuring day.

Similarly, the backline caster is likely a primary target for enemy spellcasters and ranged attackers. Going prone may help but it again paints a target for any enemy melee within range - they should take an opportunity attack if it means attacking a prone enemy caster at advantage.

Yeah, I assume that every enemy will try to target the backline caster. It is just that in spite of that, I've found it's pretty easy for a backline caster in a competent party to avoid most attacks. It's simply not the case that your average enemy could teleport; most enemies have to take the move action to get to you and there are lots of ways to make the move action fail. Also, it depends on the terrain; in dungeon it's obviously really easy to just block the whole dungeon passage unless your enemies are incorporeal making you 100% safe, whether through a summon, a duration CC effect, or an ally.

[KorvinStarmast]

I'd say no. I concur.
There's a nice graph on the Resilient/Warcaster in this post (https://rpg.stackexchange.com/a/130722/22566).
Lucky is only 3 times per day. Resilient and Warcaster are "always on" for when their features are needed.