I just DMed a year-long campaign that went from level 1 to level 20. We had two barbarians in the group, a Frenzied Berserker and a Bear Totem, and one Champion fighter who splashed 3 levels of barbarian and got Frenzied Berserker.
Yes, barbarians are overpowered. Their damage resistance is just ridiculous. It synergizes too well with high hit die, high Con, and Reckless Attack -- which in turn synergizes super well with GWM and any sort of crit-fishing build. The Champion fighter + Frenzied Berserker was the most egregious, because by 20th level they had 3 attacks + bonus action Frenzy attack + 2 action surges + Reckless Attack + GWM + crit range 18-20. So if that character decided to nova they could make 7 attacks with +6 to hit, 2d6+17 damage and a 68% chance of at least one crit -- rerolling 1's and 2's on damage dice. BUT the single-classed barbarian characters were also quite formidible -- one guy was resistant to everything except psychic damage and had a shield for a ridiculous AC and was basically unkillable, and the other guy was a clever player who made great use magic items to move about the battlefield and disrupt the enemy. I think all three of them had the Toughness feat. And it wasn't just at level 20, either; the whole way there, these barbarians were unstoppable. It was a problem because some of the other members of the group (wizard, sorcerer, blood hunter) were very squishy, and that kind of defensive discrepancy is hard to build encounters around. Like a hit that could one-shot the wizard would take away like 1/4 the barbarian's hit points. That's not very scary for the barbarian, and it sort of forces certain tactics, which sounds like a good thing except those tactics got very repetitive.
To be clear, it's mostly the resistance that I found problematic. The multiclass crit-fishing build is cute and all, but that's not the barbarian's fault, it's just a really good multiclassing combo. One of the things that makes it good is that the resistance effectively doubles ALL your hit points, regardless of how many barbarian levels you have.
If I were designing 6E, I'd ditch the resistance, and say that when a barbarian starts raging, they gain temporary hit points equal to twice their barbarian level. That's simple and it's similar to 3E's Con+4, and it's only based on barbarian levels, and it's not unduly affected by Con score or Toughness feat. Plus it gives barbarians a reason to occasionally re-rage in the middle of a fight. And if the barbarian already has some temporary hit points from another source (which is not actually very common, but it can happen, like if someone in the group has Inspiring Leader) it might give more incentive to NOT rage right at the start of a fight. I'm sure there are other fixes that could be applied; temp HP is just the best one I've thought of so far.
Yes, barbarians are overpowered. Their damage resistance is just ridiculous. It synergizes too well with high hit die, high Con, and Reckless Attack -- which in turn synergizes super well with GWM and any sort of crit-fishing build. The Champion fighter + Frenzied Berserker was the most egregious, because by 20th level they had 3 attacks + bonus action Frenzy attack + 2 action surges + Reckless Attack + GWM + crit range 18-20. So if that character decided to nova they could make 7 attacks with +6 to hit, 2d6+17 damage and a 68% chance of at least one crit -- rerolling 1's and 2's on damage dice. BUT the single-classed barbarian characters were also quite formidible -- one guy was resistant to everything except psychic damage and had a shield for a ridiculous AC and was basically unkillable, and the other guy was a clever player who made great use magic items to move about the battlefield and disrupt the enemy. I think all three of them had the Toughness feat. And it wasn't just at level 20, either; the whole way there, these barbarians were unstoppable. It was a problem because some of the other members of the group (wizard, sorcerer, blood hunter) were very squishy, and that kind of defensive discrepancy is hard to build encounters around. Like a hit that could one-shot the wizard would take away like 1/4 the barbarian's hit points. That's not very scary for the barbarian, and it sort of forces certain tactics, which sounds like a good thing except those tactics got very repetitive.
To be clear, it's mostly the resistance that I found problematic. The multiclass crit-fishing build is cute and all, but that's not the barbarian's fault, it's just a really good multiclassing combo. One of the things that makes it good is that the resistance effectively doubles ALL your hit points, regardless of how many barbarian levels you have.
If I were designing 6E, I'd ditch the resistance, and say that when a barbarian starts raging, they gain temporary hit points equal to twice their barbarian level. That's simple and it's similar to 3E's Con+4, and it's only based on barbarian levels, and it's not unduly affected by Con score or Toughness feat. Plus it gives barbarians a reason to occasionally re-rage in the middle of a fight. And if the barbarian already has some temporary hit points from another source (which is not actually very common, but it can happen, like if someone in the group has Inspiring Leader) it might give more incentive to NOT rage right at the start of a fight. I'm sure there are other fixes that could be applied; temp HP is just the best one I've thought of so far.