Originally Posted by
Constellation
To be fair, when it comes down to game play and game mechanics, making a demon hunter a fourth spec for a warlock works a lot better than jamming it into the current class lineup and trying to have it not be a hybridised version of a warlock, death knight or rogue with a few "signature" moves. When it comes down to the gameplay aspect, lots of "unique classes" are variations of the playable class. Beast Masters and Rangers are an example of two distinct classes rolled into the Hunter class and manifested in BM and SV specs, respectively. The reason necromancers don't get their own class is because a Death Knight, as far as gameplay is concerned, is a necromancer, specifically unholy spec.