From an End-game Warrior's perspective:

Paladin has the edge but not by much. Gear really plays a big role but it balances out once you have the same end-game gear or close. Warriors need the gear more than Paladin since they scale off of Vit. Our hp at end-game will easily be enough to outweigh the lack of mitigation we have.

I've tanked Titan Hardmode so this is just my opinion on the matter. A buff would be nice but nothing revolutionary. Defiance just needs a little more tweaking. I end up not being able to use Inner Beast as much as I would want to due to having the need for the 15% extra healing.