Bacon Bits
Hero
I'm jumping in late, but going to reply to OP all the same.
Damage resistance is sick. I've watched it demoralize the DM in some combats, particularly when he keeps rolling odd values for damage, or when the Barbarian has Bear Totem and makes their save against some AoE effect. "The fire blast does 38 points of damage." "I'll take 9." However, damage resistance is the primary trick that Barbarians have. Reckless attack is decent. Amazing in situations where the creature doesn't make attack rolls. But beyond that there isn't all that much there combat-wise.
Advantage on initiative is nice, but initiative is generally overrated. Danger sense is very good if you've got Dex 14 or better. It can be pretty pointless if you don't at higher levels, since advantage works poorly with poor abilities and high DCs. Fast movement is good, but nothing stellar.
I've seen someone try a Dex Barbarian in actual play. They're actually pretty terrible. Ours lasted about 3 sessions before he rearranged his character to Str. You lose just enough benefits that really add up into making the class significantly less potent.
1. Reckless attack only works with Str attacks
2. Rage's bonus damage only works with Str attacks
3. Rage gives you advantage on Str checks and saves, but with low Str, you're still likely to fail. Remember, advantage is at it's strongest when you need a 10 or 11 on the die to succeed.
Playing a Dex Barb just makes you feel stupid as a player because you're weakening all your best features and getting like +1-2 AC in return. It's just not worth it.
Sure, if you have Dex 20 and Con 24, you can get to AC 24 with a shield, but that's at level 20. That also requires spending all 5 ASIs on ability scores and requires starting play with 18, 16, 16 or 17, 17, 16 or better (i.e., 50 total points) after racial modifiers. Remember, Dex Barbs suck. It's also very difficult to increase your AC as a barbarian if you rely on unarmored defense. You can use a shield, bracers of armor, and rings/cloaks of protection. That's about it.
Don't compare classes at level 20. Don't even compare them at level 18. First, you're very unlikely to be playing at that level. Second, even if you do play at that level, it's likely to be a fraction of your campaign. I mean, at high level a Champion Fighter with three extra ASIs is likely to have Wisdom save proficiency from Resilient, 20 Dex or 20 Str and decent Dex, 20 Con, 3-5 attacks a round, higher AC, equivalent base damage or accuracy due to weapon style, and also regenerates ~10 hp every round for free when they're below half max.
Barbarians are tanks. They take a lot of punishment at every level and deal reasonable damage. However, their big failing is that damage falls off after level 11 compared to Fighters and Paladins.
Barbarians have pretty terrible class abilities in general above level 7 (with 8, 12, 16 and 19 being exceptions as ASIs, and 20 being an exception that's a special ASI) which is quite a large range of bad abilities. They're a pretty front-loaded class as far as interesting crunch. Brutal Critical, Relentless Rage, Persistent Rage, and Indomitable Might are all pretty awful abilities.
Brutal critical is, at best, a 5% chance of +6, +12, or +18 damage. On average, that's less than 1 bonus damage per attack. Mathematically, it's bad. It's not worth one class level as written, let alone the three that it consumes now. Bonus Rage damage is a better ability, and that's just one part of Rage. Sneak attack is far, far better, and that only takes one level's ability and still scales with level.
Relentless Rage and Persistent Rage should both essentially only come up when you're losing or something has gone off the rails. They're not awful, but if everything goes even remotely to plan then these abilities do nothing. Persistent Rage is particularly awful, because the primary limitation of rage at high levels in my experience is the 10 round limit, not being unable to attack something or take damage. The least that Persistent Rage could do is increase the duration to a couple minutes!
Indomitable Might is also not that great. It's exceedingly unlikely that you won't have a 20 Str by level 18 and you're all but guaranteed to have Athletics proficiency. That means you'll have a +11 to your die roll, meaning you'd need to roll a 9 to roll a 20 on most Str checks. In other words, the free 20 is below average. Since you're a Barbarian, you can also always rage to get advantage, and you've got 6 rages to burn through. So this ability essentially says, "If you roll less than 20 when you roll d20+11 (with advantage), you get a 20." It's like saying you can take 10 on Str checks. And, again, how often is that coming up at level 18? Are you still bashing doors at level 18? I suppose you could be shoving prone, but even that isn't that relevant.
Damage resistance is sick. I've watched it demoralize the DM in some combats, particularly when he keeps rolling odd values for damage, or when the Barbarian has Bear Totem and makes their save against some AoE effect. "The fire blast does 38 points of damage." "I'll take 9." However, damage resistance is the primary trick that Barbarians have. Reckless attack is decent. Amazing in situations where the creature doesn't make attack rolls. But beyond that there isn't all that much there combat-wise.
Advantage on initiative is nice, but initiative is generally overrated. Danger sense is very good if you've got Dex 14 or better. It can be pretty pointless if you don't at higher levels, since advantage works poorly with poor abilities and high DCs. Fast movement is good, but nothing stellar.
I've seen someone try a Dex Barbarian in actual play. They're actually pretty terrible. Ours lasted about 3 sessions before he rearranged his character to Str. You lose just enough benefits that really add up into making the class significantly less potent.
1. Reckless attack only works with Str attacks
2. Rage's bonus damage only works with Str attacks
3. Rage gives you advantage on Str checks and saves, but with low Str, you're still likely to fail. Remember, advantage is at it's strongest when you need a 10 or 11 on the die to succeed.
Playing a Dex Barb just makes you feel stupid as a player because you're weakening all your best features and getting like +1-2 AC in return. It's just not worth it.
Sure, if you have Dex 20 and Con 24, you can get to AC 24 with a shield, but that's at level 20. That also requires spending all 5 ASIs on ability scores and requires starting play with 18, 16, 16 or 17, 17, 16 or better (i.e., 50 total points) after racial modifiers. Remember, Dex Barbs suck. It's also very difficult to increase your AC as a barbarian if you rely on unarmored defense. You can use a shield, bracers of armor, and rings/cloaks of protection. That's about it.
Don't compare classes at level 20. Don't even compare them at level 18. First, you're very unlikely to be playing at that level. Second, even if you do play at that level, it's likely to be a fraction of your campaign. I mean, at high level a Champion Fighter with three extra ASIs is likely to have Wisdom save proficiency from Resilient, 20 Dex or 20 Str and decent Dex, 20 Con, 3-5 attacks a round, higher AC, equivalent base damage or accuracy due to weapon style, and also regenerates ~10 hp every round for free when they're below half max.
Barbarians are tanks. They take a lot of punishment at every level and deal reasonable damage. However, their big failing is that damage falls off after level 11 compared to Fighters and Paladins.
Barbarians have pretty terrible class abilities in general above level 7 (with 8, 12, 16 and 19 being exceptions as ASIs, and 20 being an exception that's a special ASI) which is quite a large range of bad abilities. They're a pretty front-loaded class as far as interesting crunch. Brutal Critical, Relentless Rage, Persistent Rage, and Indomitable Might are all pretty awful abilities.
Brutal critical is, at best, a 5% chance of +6, +12, or +18 damage. On average, that's less than 1 bonus damage per attack. Mathematically, it's bad. It's not worth one class level as written, let alone the three that it consumes now. Bonus Rage damage is a better ability, and that's just one part of Rage. Sneak attack is far, far better, and that only takes one level's ability and still scales with level.
Relentless Rage and Persistent Rage should both essentially only come up when you're losing or something has gone off the rails. They're not awful, but if everything goes even remotely to plan then these abilities do nothing. Persistent Rage is particularly awful, because the primary limitation of rage at high levels in my experience is the 10 round limit, not being unable to attack something or take damage. The least that Persistent Rage could do is increase the duration to a couple minutes!
Indomitable Might is also not that great. It's exceedingly unlikely that you won't have a 20 Str by level 18 and you're all but guaranteed to have Athletics proficiency. That means you'll have a +11 to your die roll, meaning you'd need to roll a 9 to roll a 20 on most Str checks. In other words, the free 20 is below average. Since you're a Barbarian, you can also always rage to get advantage, and you've got 6 rages to burn through. So this ability essentially says, "If you roll less than 20 when you roll d20+11 (with advantage), you get a 20." It's like saying you can take 10 on Str checks. And, again, how often is that coming up at level 18? Are you still bashing doors at level 18? I suppose you could be shoving prone, but even that isn't that relevant.
