(Just noticed your avatar is Invincible, that is great.)
I wouldn't say /that/, personally. I do, however, believe that the Scourge should have been a playable faction. Before WotLK, they were just as big a competitor for Azerothian domination as the Alliance and Horde. It would have been interesting to see Scourgified versions of the classes. Of course, that would just complicate things immensely... but still! Blizzard would please a pretty big section of their fanbase.