Quote Originally Posted by JackFross View Post
Bottom line:
A Tank with a skill that costs health to use is immediately unequivocally undeniably a worse Tank than the next Tank who DOESN'T spend health to do damage."
Oh really. I'm sure every warrior that changes from defiance to deliverance and immediately loses a large chunk of health (as max health decreases) is immediately unequivocally undeniably worse than another tank.
Oh wait, warrior is a very good tank in FFXIV.

The situation isn't as simple as you're trying to make it. It would certainly be possible to allow dark knights to drain their own health to attack. Of course there would need to be some way to balance it, like increased incoming healing or a combo skill or cooldown that restores health. So in the end the health draining tank would probably feel about the same as any other tank. I agree on that part.