Originally Posted by
ringpriest
League of Legends.
It's not technically an MMORPG, so doesn't occupy exactly the same niche, but last I saw it was at over 30 million registered players. (And it's not like WoW pays more than lip-service to the RPG element anymore anway - I don't know what the difference is between playing LoL, and sitting in a BG or Arena queue in Org or Pandaria, but I suspect it's not that much.) I don't think anything is going to out-WoW WoW; what's going to kill it is something completely outside the traditional MMO box, something like an order of magnitude better version of Second Life, some augmented reality game using Google Glass, or an actually successful merge of tabletop RPG with online MMO gaming.