You can't compete with WoW. It may be sad but it's true. Nothing has come even close to competing with WoW. The only thing that is going to topple that behemoth is time. As players get tired of it they may leave for other games. However, then you have to wonder as well if people will just end up too attached to their characters to leave the game they've spent so much time on.
I agree Fusion the only way Wow is going to start being faded out is when blizzard stops making new exp packs aka the game ends. Too many of the hardcore MMO players are neck deep in Wow have put too much time in the game to just give up and move on, as long as they are still having fun. Casuals may make up the majority of MMO players but a game wont go anywhere if it only has casuals playing, the Hardcore MMO players keep games running, AH stocked, share knowledge, etc.
Every new MMO my guild has about 5-10 people try the new MMO out, about a month later they have canceled the new MMO and are back to playing an alt instead.