Let's just wait for Diablo III, I know Blizzard always makes games that are fun for millions, even if other millions don't like it. I myself don't like World of Warcraft, but there's about 50 million unique account owners for it, it is popular, and it seems to be addictive and fun for those who do play it regularly. I still believe to this day that the best RPG (or I should maybe say action-RPG) I've ever played is Diablo II, with Baldur's Gate II following just behind (I just prefer the more action-oriented approach in DII, but the story of BGII is superior, they're technically both masterpieces in my book).
If BioWare can take the risk and certain challenge at making Baldur's Gate III, and if we also have DIII thrown in, there will be no need for Dragon Age or any other extra WoW expansions or NWN expansions. I liked the original NWN though, and I recently bought Titan Quest on Steam which surprised me by its resemblance with Diablo II (I mean a LOT), which I thought was surely fun and that it would allow me to experience a similar game than DII until DIII comes out. I'm just expecting a lot from Blizzard, but I know they'll deliver, they have to, and they're not EA, so the risks of seeing the Diablo franchise going down the drain is very thin to non-existent.