Actually to solve the problem there is a way, and a strange one at that: Bringing back HP-percentage based healing! That would make a VIT tank much easier to heal in healers' PoV, all the while not breaking the DPS-oriented fight as the healers now will be able to do more DPS on behalf of the tanks.

But of course, it's just my opinion and will most likely be overlooked by Square Enix. They still haven't even fixed PLD's endgame situation.....