Edge and Flood costs 3000 MP. Warrior damage up buff costs one GCD combo but more or less never will fall off as it costs nothing.
It will be interesting to see how much a 400 potency heal gives Warriors on Nascent and Bloodwhetting since the heals will be on average the same for each GCD regardless of what it is. Might be a nerf from current Nascent given the HP restore on IR Cleaves are 10k or more and Inner Chaos heals are running close to 20k heals per hit. But on the same token every 25 seconds you are healing yourself and also getting 10%-20% mitigation on top of a damage shield. Crazy.
And when you get into AoE in big pulls you may as well be invincible for those 8 seconds in EW with lots of targets.
Unlike Warrior, Dark Knight can't come back from lots of damage and relies on a healer big time. A Warrior played right can sustain a whole lot of crap WITHOUT a healer and if it uses all it's oh shit heals can Holmgang and become the comeback king.
Which it's looking like only Warrior and Paladin will be capable of doing.
If you solo content in Bozja right now if things go south for a Dark Knight or Gunbreaker you're in for a bad time. Warrior or Paladin though has a lot of tools to afford mistakes and come back from it without assistance.
It's ridiculous in Bozja when as a DRK you really only have Souleater or Abyssal. Meanwhile Warrior can just go "oh I lost 30k health? No problem." And heals it right back up. And TBN can only prevent damage once every 15 seconds but after that you are screwed once the shield breaks with the lack of sustain options. And it costs MP. All those other TBN tank abilities the others have? What does it cost? Free. Just UGH.
Endwalker additions for all tanks with the exception of Dark Knight look very promising mitigation wise.
