Sorry but I really don't think WoW is all that great of a game. In fact I'd say that EQ2 is a better MMO. WoW had the fanbase before it even got underway...but also the development muscle of Blizzard who are nothing if not anal about game polish and presentation.
WoW didn't break any new ground or bring any innovations to MMOs...it just avoided many of the pitfalls that it's predecessors did. It's not exceptionally deep, nor is it's combat all that engaging. Its just really easy for people to jump in and play. I really can't understand the obsession people have with it...but then it seems to me that most of the people who play it never really played any other games or MMOs before. So Blizzard tapped an audience that MMOs have never been able to tap(non-gamers), and because they got there first, I can't see anyone really ever catching up them at this point.