That would be a ridiculous decision. WoW is playable on most computers because they don't overdue their art resources. 9 million subscribers means keeping it simple.
Ridiculous indeed. In times where terms like Next-Generashun has become a religion, and where even the way superior Quake3 engine would prolly insult the capability of an iPhone now, one may wonder what has driven Blizzard into such odd decision.
On a more serious note, I understand that the majority are probably Chinese customers who can't afford a Bok Rig , but really... they could at least take the engine to SM 2.0 at least and maybe up the Polycount to 200-300%. It still would remain a Low-End game for most rigs out there.
the very reason for the low end graphics and cartoony look is because they want it to be able to run on a computer that's old. That mixed with the fact that you can sometimes feel like you've done alot in an hour hits the PERFECT bullseye for the much desired casual market.