It's meant to represent the fact he is using TWO blades, so it seems obvious that he can kill two opponents from one hit. "These are treated as
a power weapon that can cause 2 wounds for each hit inflicted (this means that 2 wound rolls are made for each successful hit). " Seems pretty clear.
Even though I dont use him much, since he's such a lush mini I do bring out on occaision at friendlies. Unlike some others here, I'd prefer to save him for 2000+ pt games, so I can have an independendent drugged up SF super Archon and have a squad of incubi lead by a minimalist Dracon with Six Incubi and Drazhar. Now for such a squad, Drazhar's ability to swap places with the Lord is handy as the Lord has a sucky save.I generally find my cheapo Dracons die quite quick, so the squad ends up being entirely Incubi! It's fiun when someone sets up a charge with no power weapons but a amphetamine parroteload of attacks, and you swap Drazhar for the Lord, getting his much better save!Add this to the fact of his extra wound and there's plenty of times when you can usefully swap out the Dracon.
Drazhars for those games where fun is the only aim. Perhaps your opponent brings out his super expensive HQ retinue as well. ALlows for a nice change form those balanced armies that are used in tournament play, which are gretarmies, just they aren't the be-all and end-all.