How would you fix Warrior?

[Duelle]

That's not entirely true. See: http://www.wowhead.com/spell=49998

The real key, like you said, is that it has to scale off of *incoming* damage, and not be primarily tied to any stats possessed by the player.

Yes and no. The value of Death Strike is half the amount self-healed and half the resulting Blood Shield, which plays into mitigation gained by DKs from armor, inherent mitigation via parry & dodge, and cooldowns like Icebound Fortitude and Bone Shield. If anything (and this has been said before), the self heals+Blood Shield are there to compensate DKs not having access to shield block mechanics like other tanks (prot warriors and prot paladins).