Yeah, lots of opinions out there, not too much skill though. Once someone goes beyond simply coming up with an idea but puts it into practice, then they may have something going. Most ideas never even make it to paper though, and until that happens it hardly even a real idea but just an opinion.
I see a lot of interesting stuff being developed in the independent dev communities, but it seems like most of the well known commercial developers got stuck on the hamster wheel; just spinning the same stuff to be on the safe side. Investors are fickled though, projects can take additional time to complete compared to other genres (excluding duke nukem forever), so they want results and some assurance that the game will gain revenues, so you now get a choice of what flavor of WoW you prefer. Ah, I think we would be in better shape if that game was never even put to paper, ah well.
So what world/concept? For me, the one Im working on no doubt. For you, maybe WoW, dont know. For them, what ever they choose, Im sure.