Honestly, all tanks needs the kind of TP management that the WAR has while in tank stance.

Setting aside the TP regen skill(because it's not available in Defiance), WARs get a LOT of longevity just from using Inner Beast, because it's a GCD that didn't cost TP.

PLDs and DRKs could use that kind of thing as well.
Shield Swipe should be free, and DRK should get.. something. I'm thinking either a proc that increases Unmend's potency, or redesign Reprisal to have Shield Swipe's mechanics but that might be too samey?