Oh, not trying to start an argument (well, I'm not at least). I'm just trying to offer the following advice: The reason you "lost" that game wasn't explicitly because you couldn't 2v1 the blood dk down. You shouldn't have lost a teammate to begin with, since a blood dk is so easily kited and doesn't put out enough damage. That might be a gear issue, and sometime that just happens, but the errors you made that caused you to lose the game were allowing your hunter to die in the first place.
Again, not starting a fight, just offering advice
Double blood DKs do totally suck when I'm doing 2v2 for conquest and am too proud to just leave