You want to play as a Dragon? Fine!
Penny Arcade's comic earlier this week focused on a recent Dungeons and Dragons Online preview of Module 6, and included commentary on the state of the MMOG market in general.
The reality is that it wouldn't matter if the game were completely incredible. The game could be as good as World of Warcraft, and even this would be insufficient. It would have to be better than WoW to succeed, now. I'm exceedingly curious about both Warhammer and Age of Conan, and both have chosen on multiple occasions to apply another coat of paint. With a head start, years of steady improvements, premium upgrades, world-class art and design, and hundreds of millions of dollars, Blizzard is an entrenched foe. They have a "next generation MMO" in the pipeline, but my guess would be that it's a graphical update to the existing world. There's ten million people playing it. You don't make a sequel to that game. You exult in it.