Originally Posted by
Mionelol
You don't get balanced around 5-man heroics and challenge modes, you get balanced around heroic raids, and in heroic raids, blood DK damage is, at best, equal, and at worst, mediocre, when you compare them to the other tanks. The same logic goes with their survivability - in raids DKs get gibbed very easily, in 5mans they're virtually immortal. This is the design of the class, having the entire mitigation system being reactive instead of just a part of it.
Without Vengeance (or very low amounts like you get in 5mans) DKs absolutely rock every other tanking class though, this is true.