When doing this sort of thing you want to avoid using placeholder numbers. It draws attention to the numbers instead of the concept and that will cause you undue frustration.

That said, concept is still way too strong. The HP cost would have to be much larger on some of these skills to be balanced. Especially the one that relegates damage to a fixed of your HP per hit for a few hits. It's like 'Hey, we can completely negate mountain buster and then receive a healing boost after it, for free!' You're very forgiving on the sacrifice aspect, to the point where the DK using its sacrifice skills isn't really a sacrifice at all, considering that HP is just gonna get healed right back up before the GCD completes. That DK basically gets ridiculous bonuses for free.