Some things need to be said: Warrior does the most damage on its own because it can self-boost its damage through Storm's Eye. Paladin does a slight bit less damage than Warrior and Dark Knight, but this is made up by their incredible healing utility that is unmatched even by Warrior. Dark Knight and Warrior deal roughly the same damage as off-tanks given equal skill and item level once accounting for debuffs, with a brazen Dark Knight pulling ahead while actively tanking thanks to their parry-based procs.
So, the real problem with Warrior is not their damage output. It hasn't been their damage output for a few patches now, if not the entire expansion. It is that Warriors have a perfect storm of power going on. To list them off:
- They possess two powerful supportive debuffs, the Storm combos. One of these is even irreplaceable, there is no other Job in the game that can provide Storm's Path.
- The best and most reliable defensive "cooldown" in the game, Inner Beast.
- A much more effective way of mitigating damage: HP and damage reduction is better than just stacking damage reduction.
- Warriors are extremely self-reliant between their high health restoration through attacking their enemies and their TP restoration.
- And Warriors are the only tank whose enmity combo is also their most effective way of dealing damage.
All of that combined leads to Warrior being too strong for the other two tanks really compete. Add to it that Rage of Halone and Delirum are not damage reduction, but stat reduction, and the issue is compounded because of how stats tie into the damage calculations of enemies. So really, the issue isn't that Warriors do more damage, it's that they do everything else too well.