I get really tired of the way some threads and articles, with extreme naivety, assume that all or most MMOers want the same thing. A more realistic and useful approach might be to try to map out the factions among MMO gamers. What kind of factions have you all observed? Sandbox vs. Themepark? Questing vs. No questing? PvP vs. PvE? Helpy maps and quest compasses vs. the player has to work to not be lost? Minigames vs. no minigames? World marketplace vs. player shops?
I want to help design and develop a PvE-focused, solo-friendly, sandpark MMO which combines crafting, monster hunting, and story. So PM me if you are starting one.