As I have said before, what makes an mmorpg fun and worth playing, is the people. Unless you've got peeps to roll with, they simply get boring. Reason being, community often makes or breaks a game. They are sort of like the icing on a cake. It's not the main focus, nor is it the bulk of the meal, yet it provides the flavor and appealing finesse. Good icing on a bad cake will still trick people into eating it, but bad icing on a good cake makes for one dessert none will try. While plenty of people are trying WoW, it's still that poor icing that cause many others refuse to touch it. Developers can code gameplay, they can write an entire world's lineage, and they can bring it all to us on our computers, but they cannot control what the community becomes.
While many people, including myself, have knocked WoW, it in itself is a perfectly fine game. It's just an unfortunate cake with bad icing.