they have made it worthwhile
15minute enslave, 100% will last that long. at end it despawns. and the doomguard is our most powerful pet, so for a boss fight that you know your guild can do, summoning this guy is brilliant. heck personally I believe I'll be popping my inferno at about 1minute remaining on a fight.. that or go for an interesting dest spec which allows me to use my imp till it's OOM, summon an inferno, when that dies instant summon a new imp :)