Honestly, Sony is making the next leap in MMO's, and Blizzard knows it. This is a smart move on their part. The two biggest challenges a "true" next gen MMO has to overcome are 1.) The ability for players to drive content creation AND allow the world to evolve constantly to consistently give that feeling of exploration/learning. 2.) An extremely in depth and powerful AI, to help make point 1 work (IE NPC's change behavior, so old encounters become new). It's telling that one of the features Blizzard wanted to emphasize in this MMO is essentially what Story bricks is trying to do; an advanced AI that adapts and responds to human interaction. If there really were an AI like that, the game world itself would start to evolve content...Combine that with a world where players can build things? And it might just be the real "next gen". I believe Blizzard was working on the AI, but realized that they wouldn't have Voxels, and decided to wait.
Outside of truly advanced AI system and a world which can change through player action--the only other real staggering advance I can imagine is going to be the UI (Namely, Virtual Reality.)...But I think AI is theBIGthing, imo. The more I've played games recently, the more I've come to realize that AI is THE defining factor that is holding everything back. It's the element that is pretty much keepinggreatgames from being perfect. And I think, really, that is one of the primary reasons the whole MMO space took off in the first place--because human players just provide tons of immersion, depth and creativeness. Hell, most genres, like Strategy, to FPS, have just stagnated into online match ups because the AI is so terrible that either it has to cheat obscenely to be challenging (And then it's just frustrating) OR it's a push over because it can't adapt to simple strategies. (It's especially hurting very complex strategy games like Civ and TW; the AI is just garbage.)
Just imagine though; how ridiculous a game like Skyrim would be if every NPC thought, and acted, like a human. It would be the ultimate game, constantly changing, constantly adapting--your choices wouldn't just have an impact, they would CREATE new games for you to play. Now, Idon'tthink MMO's/Games will get to that in the next few decades...but I think a small step forward would still be revolutionary. Hell, NPC's JUST altering behavior based on previous interactions (In a meaningful way--IE like adapting tactics. Raid a town, have it build walls ect), would be enough, for me at least, to classify something as "Next Gen".
Just my .02$ but this seems like a smart move on Blizzard's part. The industry seems like it's on the edge of a big change (Like it was back in 1997). Either VR, or AI or Voxels--something big. Blizzard is going to do what Blizzard does best, and steal that shit and make it better with their ridiculous engineers.