Fixing the Armor Table

[Sindri]

Why I think there's a problem:
The RaW armor table in 5e makes no sense. At all. I have major problems with more than half the armor types listed. And since there's nothing like a coherent logic behind the design, there's no way to remember the different kinds of armor without either just memorizing the whole thing by rote, or continually looking things up in the book and holding up game time.

-Padded armor applies disadvantage to stealth. Why? How? The only answer I can come up with is they needed some way to make it worse than leather, but were unwilling to give leather a second point of AC, because...
-They insist on including "studded leather". I know it's tradition at this point, but seriously, this entry on the table just shouldn't exist. Because studded leather just doesn't exist. It never did. Think about it rationally, how would adding a few dozen rivets to a suit of leather make it stop swords and arrows any better? Are you relying on the one-in-a-thousand chance of the sword striking exactly on the head of the stud, and then for some reason bouncing off instead of sliding off the side and continuing to cut through the leather? I'm pretty sure the whole 'studded leather' meme started with some writer looking at a suit of brigandine, not having any idea that there were big solid metal plates inside there, and assuming that the rivets themselves somehow projected a magical protection field. It's time to put that idea to rest.
-Scale Mail. The game mechanics say that it is strictly worse than all your alternatives, regardless of circumstances, so why would anybody ever wear this? And if nobody would ever wear it, why is it taking up space in the book?
-Half Plate. Also known historically as 'plated maile', 'plate and maile' or the common modern term of 'platemail'. Consists of solid plates of steel over the parts that don't need to bend, and chain over the parts that do need to bend. Essentially, a heavier but more protective version of chainmail. So why in the name of all the gods is half plate classified as "medium" while chain is classified as "heavy"?
-Ring mail. This is studded leather all over again, but somehow worse. Yeah, just make the studs bigger and heavier, that will totally prevent somebody from just stabbing you through the multi-inch gaps between them where you're just wearing leather! Never existed in the real world, doesn't make any kind of logical sense, and as an added bonus the game mechanics make it completely worthless because anybody who can wear it will have better as part of their starting equipment. Why is this taking up space in the book?
-Chain mail. See half plate.
-there's just a lot of wasted spaces. Nobody would wear Leather if they had 45gp to their name, because Studded is mechanically strictly superior. Nobody would wear a chain shirt instead of a breastplate, or scale instead of half plate. There's a clear "right answer" in each of the three categories, and no reason to ever choose differently, so why are there all these wrong answers presented to you?

So, while I initially tried to just run 5e by the book, I couldn't stand this. And since it would be more work to try to fix what's already there than to just make up something new, I'm ripping out the whole table and making up my own.

Main goals of this project, in order of priority:
1) Every entry on the table needs to serve a purpose. If there isn't some circumstance in which this is the best choice then nobody would be wearing it, which means nobody would be making it, which means we shouldn't waste any time and energy writing or talking about it.
2) The whole table should make sense, logically and where possible historically, so we can save our suspension of disbelief for things that make the game more fun.
3) The whole table should be easy to remember, so you never need to hold up the game by looking things up.

lower priorities include:
4) Within each category, there should be some opportunity for PCs to improve their gear as they advance and get access to better resources
5) Within each category it should be possible to achieve AC 18, but no higher, and it should always be difficult to do so
6) The most iconic armors depicted in fantasy books and art (leather, chain/scale, full plate) should be the ones most Heroes are wearing at high levels once they can afford whatever they want.

After some consideration, I gave up on trying to describe every single possible style of armor, and instead separated each kind into three 'tiers' of increasing protection and increasing weight/drawbacks. Within those tiers I'll list common examples, but allow for variation based on the character's personal style, the culture/technology of the region, etc. For example, chain and scale will be mechanically identical, and therefore only use one slot on the table, but you can choose whichever you think is cooler. This also means that any time a new or exotic form of armor is introduced, it can generally be slotted smoothly into one of the existing categories rather than needed an entire set of homebrewed stats.



tier
AC
cost
weight
special


Light






1
11
5gp
5lb



2
12
20gp
10lb



3
13
100gp
20lb
Disadvantage on Stealth


Medium






1
13
10gp
25lb



2
14
100gp
25lb



3
15
300gp
30lb
Disadvantage on Stealth


Heavy






1
16
300gp
40lb
Str 13+


2
17
1,000gp
50lb
Str 15+


3
18
2,500gp
60lb
Str 15+



Light Armor: always allows the use of your full dex bonus, does not impose a penalty for sleeping in armor, takes one minute to don or doff.
Tier 1: typically represents Padded armor, a quilted gambeson, exceptionally heavy clothing, un-hardened leather, "thieves' clothes", etc. This will never be your first choice in open warfare unless you have to equip a large force for very cheap, but it has two major points in its favor: first, this is the heaviest (mundane) protection that you can wear without making it obvious that you're wearing armor, so if you're in disguise as an ordinary civilian or trying to look harmless during a diplomatic mission or whatever, this is your best option. Second, every suit of Medium or Heavy armor comes with a free layer of padding underneath, which means you have something that you can sleep in, or put on when you don't have time to don your real armor, that's significantly better than nothing.
Tier 2: most likely, this is your classic Leather Armor, hard plates of boiled leather arranged in such a way that they'll turn or at least slow a significant fraction of potentially deadly blows, but it could also represent clothes made from spider silk or woven through with wires or some other exotic material. This is usually the armor of choice for roguish types, because anything that gives more protection will either slow you down or make too much noise.
Tier 3: the Chain Shirt, or something similar. Light enough, and leaving the limbs unencumbered enough, to allow the wearer full mobility (as long as they can carry the weight) while keeping your vitals safer than anything softer would, but at the cost of making cheerful little jingling noises when you move. The best protection available for a high dex combatant who fights openly rather than relying on subterfuge, but inappropriate to stealthy operations. Also allows you to achieve the maximum AC of 18, but only if you have a Dex of 20.

Medium Armor: Allows up to a +2 from Dexterity, or +3 if you spent a Feat on Mastery, but no more. Sleeping in armor does not remove exhaustion, and only recovers a quarter of spent hit dice.
Tier 1: mostly represents Hide Armor, the result of just piling enough dead animal parts on to stop a blow. It could also represent wooden armor, or the scales of some tough but not extraordinary monster. This doesn't protect you as well as metal would, but has two main advantages. First, Druids can use it without penalty, and it's the heaviest thing they can use. Second, if you're stranded in the wilderness with only what you can gather or hunt, you can make yourself a suit of Hide when you wouldn't be able to manufacture anything else except for tier 1 Light.
Tier 2: this covers things like Brigandine which grant reasonable protection to the whole body while remaining relatively flexible, as well as things like a Breastplate which grant excellent protection to the torso alone while leaving other body parts undefended. This will be the standard equipment for a lot of professional soldiers, hitting a sort of sweet spot between protection and expense if you need to equip a small army or mercenary band. For player characters and other elite forces, this is the heaviest that armor gets without impairing Stealth.
Tier 3: primarily Chain or maile, but also covers Scale, some of the lighter forms of Lamellar, etc. The best protection that you can get without losing your Dex bonus, and the best you can wear without slowing down if you don't have high Strength, making it the armor of choice for dedicated high ranking warriors and nobles who don't like the restrictions of Plate. It also allows you to reach the max AC of 18, but only if you spend a Feat on Mastery and you have 16+ Dex (but if you do spend that feat, you also remove the penalty to Stealth, so that's a very real option at higher levels).

Heavy Armor: All forms remove your entire Dex bonus (or penalty), all forms impose Disadvantage on Stealth, and if your strength is below the requirement listed (and you aren't a Dwarf) your movement rate is reduced by 10. Ten minutes to don, five minutes to doff, assuming you have somebody around to help you with the straps. Without assistance, times are doubled and your AC is reduced by 1.
Tier 1: Splint mail (chain with strips of reinforcement forming sort of incomplete vambraces and greaves and such), heavy lamellar, laminar, and other kinds of protection made from overlapping pieces of hard metal but with incomplete coverage, more gaps, or lighter plates than higher tiers. Sturdy enough most of the time, but often primitive or crudely made. Most people who wear this do so because it's the best that they can afford, or because their culture doesn't have the advanced level of technology required to make the higher tiers of heavy armor, but if your Str is a 13 or 14 and your Dex is nothing special, it might genuinely be the best option.
Tier 2: Half Plate, Plate and maile, Plated Maile, or Platemail. Anything that doesn't need to bend is made from solid, thick steel, while joints and gaps are protected by high quality chain. This is the best available in many cities in many worlds, and is the heaviest form of protection that can be worn without being precisely customized to the wearer. Generally you pick this if you've looted the best battlefields in the world but never had custom gear, or if you don't have the time, money, or connections to commission a smith to spend the better part of a year working to give you the best protection in the world.
Tier 3: Full Plate. The chain component becomes unnecessary, because even your joints are covered by finely crafted, precisely interlocking bits of articulated steel plate. Allows the wearer to move almost freely while exposing nothing to enemy attack, but only available to the wealthiest patrons and the most technologically advanced nations in most worlds. If you try to loot this rather than ordering it custom-made (or spending a lot of downtime on it yourself if you have the smithing proficiency), and it isn't enchanted to resize itself to fit the wearer, it will cost a minimum of 2d4x100gp (and a week per 50gp) for a skilled smith to modify it to fit you. Trying to wear full plate which is not precisely fitted to your body applies the same penalties as wearing armor with which you are not proficient (disadvantage to basically everything).


So, how does this all affect your starting equipment?
The class gear packs in the book all start you with either Leather, Studded, Scale, or Chain.
If the books says Leather, it means 'mid-range light armor', so you get Leather (or some other tier 2 light). Enjoy the +1 AC.
If the book says Studded, it means you're an artificer 'the best light armor that doesn't impose a penalty', so you get Leather (or some other tier 2 light). Enjoy 3lb less encumbrance and stop complaining that you don't have better gear than the rogue anymore.
If the book says Scale, it means 'medium armor with ac 14', so you get Brigantine, a Breastplate, or some other kind of tier 2 medium. Enjoy losing 20lb, not having penalties to stealth, and most importantly not wearing a kind of armor that only exists on starting characters and you would have had to throw in the scrap heap after your very first adventure.
If the book says Chain, it means 'the worst heavy armor that isn't ******* ringmail.' You get tier 1 heavy armor, of whatever style you prefer.

Now, this does mean that characters that start the game with medium or heavy armor are getting a significantly higher gp value of starting equipment than before. After thinking long and hard about the issue, I have decided to just roll with it. If you as the GM see this as an issue, just declare that your old lamellar is so rusty and dented that, while it still protects you well enough until and unless you have a chance to upgrade, you would never be able to sell the thing for more than a tenth the price of a new suit. If somebody wants to use random starting money rolls instead of the basic equipment bundle for their class you might need to throw them a bit extra, but the exact number of coins available at chargen is a tiny issue compared to the entire rest of the campaign.

Thoughts?

[Kane0]

Why would a chain shirt give stealth disadvantage or not be able to be worn discreetly under regular clothes?

[Sindri]

Because of the jangling mostly. To actually silence any significant amount of maile, you would need to wrap each individual link with cloth or something, so there wasn't metal-on-metal contact, and after a few weeks of movement I'm pretty sure that would wear through and have to be re-done regardless.

(Brigandine or Breastplate can be worn without Stealth penalties, because there's no metal-on-metal movement. The brigandine has cloth or leather between all the plates, and the breatplate is a single piece except for the buckles, which are held tight under normal circumstances. The shininess of the breastplate might give you away in the shadows, but that's easy enough to obscure.)

You could conceal it visually under heavy enough clothing, but anybody with ears would notice the concealed armor when you started moving unless you spend prohibitive amounts of time and effort constantly re-silencing it.

Unless of course you have access to mithril, which will remove stealth penalties from any armor it's made from nicely, and halve the weight to boot. Then you can have a vest as cool as Bilbo's.

That said if you really wanted a silent chain shirt, and your GM gave the OK, you could just say that's what you're using as a tier 2 light armor. Maybe excuse it as having links so tiny and so finely fitted together that they don't make any significant noise, at the cost of not giving as much protection because they're so thin. And maybe increase the price, to allow for it to be worn secretly in circumstances that wouldn't normally allow armor.

[Dienekes]

Hmm, you seem to have reached your stated design purposes. But what’s the point of heavy armor as the rarest armor proficiency to achieve, has the most expensive pieces, and strength requirements to use, if it doesn’t even provide more AC?

Honestly, this seems just a stealth buff to Dex builds who do not need it. They’re already the far more versatile option.

But if that doesn’t matter to you, then I suppose this all checks out.

[Sindri]

In RAW, Medium Armor already gives the same max AC as heavy does, if you have the Mastery feat instead of heavy armor proficiency, with improved stealth on top.

The corresponding Heavy Armor Mastery feat is one of the few sources of true damage reduction available in this game, making it still the best choice for a dedicated tank.
If you're not spending feats on your defense, heavy armor has the lowest ability score requirements in order to get good AC. You could have a -4 penalty from dismal dexterity and then just ignore it and get 18 AC anyway. Even the str prerequisite is a soft limit rather than a hard one, since -10 movement rate is inconvenient but not crippling (especially if you have a steed, or one of the many other sources of movement that doesn't care about your feet).

It is possible for dex builds to match the same AC as strength builds with the modified chain shirt, but they do so at the cost of disadvantage on stealth, and the ability score requirement is a 20 instead of just a 15. And unlike the stealth penalties for medium armor, that can't be negated no matter what feats you have. Unless you have mithril, I suppose, but that's no longer something you can just buy so it's going to either be inaccessible or treated like a major magic item in most settings. (And if mithril armor isn't super rare in your setting, that negates pretty much every downside to heavy armor at once by removing the str requirement, the stealth penalty, and halving the weight)

(I do think that the rapier should be knocked down to a d6 damage, but that's a different discussion)

[Breccia]

This also means that any time a new or exotic form of armor is introduced, it can generally be slotted smoothly into one of the existing categories rather than needed an entire set of homebrewed stats.

Thoughts?

Two.

One, why would anyone use homebrew if it doesn't do anything new? If I'm reading this right, any new armor would either be "Same as Type 2 Medium" in which case who cares, or "Same as Type 2 Medium, but also--" making it objectively better and also defeating the value of this table.

Two, why are you messing with prices? Heavy armor is much more expensive (requiring you to write up new rules to handle it) while Light and Medium armors are much less expensive. And better, @Dienekes was right.

There must be some demand for this. I think I've seen this thread idea come up...three times?...in the last month or so. I guess this one is closest to RAW so the least likely to cause stat problems.

[Sindri]

why would anyone use homebrew if it doesn't do anything new? If I'm reading this right, any new armor would either be "Same as Type 2 Medium" in which case who cares

That's exactly the point. You encounter a society that raises giant spiders as livestock and uses their silk to make clothing, you don't need to spend any effort trying to make new rules for clothing made from spider silk, you just say 'tier 2 light' and you're done. A player wants to make their new fighter or paladin be all samurai-themed, you don't need to choose between doing a lot of work for their custom equipment or rejecting them because you don't have the book for that, you just need to figure out if their dō-maru counts as tier 3 medium, tier 1 heavy, or tier 2 heavy.

This isn't a couple of new homebrew suits to add to the 12 suits that came in the PH. This is, barring magical effects, vastly more advanced technology, or materials so extraordinary that they might as well be magic, all possible forms of armor.

The prices are the part of this I'm least confident about, since the economy is screwy at the best of times, but I tried to put them where they made sense, based on who would be wearing the armor and how much skill and work is required to make it. Like I said at the beginning, I'm not trying to gradually modify what's in the book to make it less stupid, I'm ripping out the table in the book entirely and replacing it with a completely new table.

There does seem to be a lot more pushback than I was expecting to the existence of a third tier of light armor... Personally I've never encountered a character with 20 Dex who wasn't more concerned with stealth than with a single point of armor, but probably my experiences are not representative?

I don't think I can justify removing or seriously downgrading the light armors; padded is distinctly more protection than normal clothing, leather is distinctly more protective than padded, a chain shirt is distinctly more protection than leather, and a chain shirt does not impair movement by enough to qualify as Medium. To not have a form of light armor that gives 13 AC, I would need to come up with a way to justify why, across the entire multiverse, nobody ever came up with ideas that were commonplace in our own history. I could try implementing separate max dex bonuses for each kind of armor, like they had in 3.x, so tier 3 Light would give good protection at average to good but not exceptional dex scores? But I'm reluctant to add that additional layer of complexity to the game system. Maybe I'm coming at this from the wrong direction, and I need to upgrade heavy armors instead? But increasing the maximum available AC in the system seems like it would have more far reaching consequences to overall balance...

[Saelethil]

Maybe I missed it. Are you changing shields at all or do they still come with medium armor and add +2 AC?

[Sindri]

Shields aren't part of any of these categories. Shield proficiency is a separate thing from any of the armor proficiencies, though it usually comes alongside medium proficiency.

A shield can be added to any armor, or used without any armor, and gives you a +2 AC regardless of size. I thought about trying to break them up by sizes like other editions did, but ultimately decided it was easier to say that the increased mobility of a small shield and the increased coverage of a large shield pretty much cancel out to the same benefit.

And if you had anything small enough that you could strap it to your arm and forget about it instead of specifically using that limb to defend yourself, that would just be included in your armor instead of tracked as a separate thing.

[Kane0]

Hell I could see two per category instead of three. Cheap and not as good vs better but pricey. Stealth disadvantage only applies to 'good' medium armor and both heavy armors.

Edit: For example

Cheap light armor: AC 11 + Dex (max 5)
Good light armor: AC 13 + Dex (max 5)
Cheap medium armor: AC 13 + Dex (max 3)
Good medium armor: AC 15 + Dex (max 3), Stealth Disadv
Cheap heavy armor: AC 16 + Dex (max 1), Requires Str 13, Stealth Disadv
Good heavy armor: AC 18 + Dex (max 1) Requires Str 15, Stealth Disadv

Buckler: +1 AC, interaction to don/doff, requires light armor proficiency
Shield: +2 AC, action to don/doff, requires medium armor proficiency

Medium/Heavy Armor Master feat: Removes Stealth Disadv, +1 AC in light or medium armor, reduce B/P/S damage by Prof bonus in heavy armor.

[VoxRationis]

If one of the design concepts here is to decouple the baggage of describing the specifics of armor materials, why bother including features like disadvantage to stealth at Light III, which are justified with the assumption that they are the result of the specific materials used? It seems odd to me that as it stands, everyone who doesn't have a +3 Dex bonus gets more benefit out of piling a bunch of hides on themselves than from wearing a chain shirt.

[arkangel111]

Maybe it's just me but why 18? I know that is what core has but Its ridiculously low anyway. I mean a level 8 character has even odds of hitting you without a magic weapon or any spell buffs, while monsters are breaking even at what 6?
AC is notoriously bad compared to attack bonus in modern editions at least. 5E did make strides to reduce this glaring weakness but only by just reducing player options to stack bonuses. You really have to hyper focus on defense to get anything that might remotely be called a Tank. If you are going through the effort of homebrewing the Armor you might as well fix the actual mistakes rather than just effectively deleting armor options you didn't like. Not saying your reasoning isn't sound on why.
And I believe even with your rules, one of the easiest ways for ridiculously easy AC is still unarmored barbarian, so why would anyone wear armor at all? typically light/no armor builds get bonuses to their AC while its pretty much assumed if you can wear heavy armor you do, and therefore you don't get bonuses. I mean even the mastery feat for heavy armor doesn't give more ac and is realistically worthless since most creature attacks in the latter levels will count as magic and therefore will be a complete waste of a feat. I applaud you "fixing" the AC table but imo I don't think you addressed the core issues of AC vs Atk.

[Sindri]

Edit: For example
...
Cheap heavy armor: AC 16 + Dex (max 1), Requires Str 13, Stealth Disadv
Good heavy armor: AC 18 + Dex (max 1) Requires Str 15, Stealth Disadv
...
Medium/Heavy Armor Master feat: Removes Stealth Disadv, +1 AC in light or medium armor, reduce B/P/S damage by Prof bonus in heavy armor.
That's a bigger downgrade to heavy armor than anything I'd considered. If Dex bonus still applies, even a single point of it, then Dex penalty applies too, making heavy armor builds suddenly go from being okay with a 3 in dexterity as long as they had decent strength or didn't care about movement rate, to requiring a 12 dex on top of everything else they're doing, and telling anybody who rolls below-average dex that they're never allowed to be any kind of front-line combatant.

You also gave light armor a bigger upgrade than I did, albeit one that requires you to learn Medium proficiency and then spend a feat on it.
I do like the idea of scaling up the damage reduction on Heavy Armor Masters by Proficiency though, might steal that... Should I accept a 1 point downgrade on starting characters in exchange for a bonus at level 9+, or should it be proficiency+1?


If one of the design concepts here is to decouple the baggage of describing the specifics of armor materials, why bother including features like disadvantage to stealth at Light III, which are justified with the assumption that they are the result of the specific materials used? It seems odd to me that as it stands, everyone who doesn't have a +3 Dex bonus gets more benefit out of piling a bunch of hides on themselves than from wearing a chain shirt.
Losing Stealth is the inherent tradeoff in my mind for getting better protection. GMs are free to introduce new kinds of silenced tier 3 light, either as things rare enough to be treated like magic items (like mithril), or by adding some other kind of major drawback, but I couldn't think of any way to get significantly more protection that Leather without either impairing movement enough to be called Medium or making it harder to sneak around.

From a balance perspective, tier 3 light with stealth is a pure upgrade for dex builds, making light armor superior in every way to both medium and heavy (unless you have Heavy Armor Master).

And from a narrative perspective, if there's no downside to switching from tier 2 light to tier 3 light, why would anybody ever be wearing tier 2 light? And since leather armor is super common across fantasy stories, there must be a reason that it's preferable to the kinds of people you see wearing it.

But hey, if you don't have a 16 dex and you do have proficiency in medium armor, why wouldn't you trade up all the way to Brigandine?


Maybe it's just me but why 18? I know that is what core has but Its ridiculously low anyway. I mean a level 8 character has even odds of hitting you without a magic weapon or any spell buffs, while monsters are breaking even at what 6?
AC is notoriously bad compared to attack bonus in modern editions at least. 5E did make strides to reduce this glaring weakness but only by just reducing player options to stack bonuses. You really have to hyper focus on defense to get anything that might remotely be called a Tank. If you are going through the effort of homebrewing the Armor you might as well fix the actual mistakes rather than just effectively deleting armor options you didn't like. Not saying your reasoning isn't sound on why.
And I believe even with your rules, one of the easiest ways for ridiculously easy AC is still unarmored barbarian, so why would anyone wear armor at all? typically light/no armor builds get bonuses to their AC while its pretty much assumed if you can wear heavy armor you do, and therefore you don't get bonuses. I mean even the mastery feat for heavy armor doesn't give more ac and is realistically worthless since most creature attacks in the latter levels will count as magic and therefore will be a complete waste of a feat. I applaud you "fixing" the AC table but imo I don't think you addressed the core issues of AC vs Atk.
Two reasons. First, I haven't been GMing this one long enough to make major changes, especially since such things are easier to roll out than they are to roll back in an ongoing campaign. So I want to rip out this stupid table that I hate and replace it with one that makes sense, but I don't want to change the general parameters around the table or the rules which interact with the table, at least not yet.
Second, from everything I've see, AC 20 (from tier 3 armor of whichever style you prefer, plus a shield) is actually pretty damn good in this system. Non-tanks will frequently be sitting around 15, so against say, a Marilith (CR 16 monster focused on melee combat) who has a +9 to hit, your first level fighter effectively has 33% damage reduction (50% chance of hitting you, instead of a 75% chance of hitting everybody else), which is equivalent to you having 50% more HP and all your healers having 50% more effect for as long as you can stay the enemy's primary target. Plus a dedicated tank would probably have the Defense fighting style and then spend their reaction on either Defensive Duelist or Protection style for the first attack each round that would have slipped through. And that's before considering the effects of magic; magic armor and magic shield stack, in a way that you can never stack attack bonuses, and you can put a defensive weapon on top of that if you can find one to become basically invulnerable at high level (in exchange for spending every attunement slot you've got).
But yeah a well built barbarian is the tankiest class in the game by a significant margin. That's their job: hit and get hit.

Where are you getting "most creature attacks in the latter levels will count as magic" from? I counted a grand total of 19 things in the entire monster manual that count as having magic weapons. There's a bunch more in MTF, but they're all high level Fiends. Unless you're adventuring in Hell, resistance to non-magical damage will protect against almost everything you find. (Except AoE elemental attacks, but at least anybody with a shield can spend one feat to apply it to dex saves and also get the benefits of Evasion)

[arkangel111]

Where are you getting "most creature attacks in the latter levels will count as magic" from? I counted a grand total of 19 things in the entire monster manual that count as having magic weapons. There's a bunch more in MTF, but they're all high level Fiends. Unless you're adventuring in Hell, resistance to non-magical damage will protect against almost everything you find. (Except AoE elemental attacks, but at least anybody with a shield can spend one feat to apply it to dex saves and also get the benefits of Evasion)

I was also including in the magical attacks anything that deals a type of damage other than B/P/S or creatures whose main damage comes from non B/P/S, entries like: CR 8 Priest of Blight 5 (1d6+2) slashing plus 17 (5d6) necrotic. Yay! taking 19 damage instead of 22 is rarely going to be a big deal especially when you consider most monsters have multiple attacks or even more likely there are multiple of the monster.
I mean the only time that 3DR is really going to be effective is against a bunch of lower level mooks. Honestly the feat is great probably pre 5. okay up to level 8 and then flavor after that. Considering most characters are grabbing +2 to a stat at 4, by the time you'd add it to your build its already borderline worthless, especially when there are feats that will give you far more mileage like lucky. Even at CR 4 range at most you are negating their stat bonus to damage A CR 4 Githyanki Mindraider can hit for avg 20 damage with sneak attack, so negating 3 whole damage isn't going to save your life. This doesn't even include if your DM gives you magic items and treasure through equipping monsters.