Probably not ...
Personally, I expect the game to unseat WoW as the biggest MMO game on the market would be a game which is drastically different from WoW in most ways; and the only real similarities would be that the game would be easy to pick-up, highly accessible, and amazingly polished. The reason it has to be so different is to provide reason for people to leave WoW, and to get people who left WoW because they were so sick of it to try your game.