to answer your question, so far the only mmorpg game on the horizon for Xbox seems to be Citizen Zero and it's doubtful that even that will see release this generation. Expect to see that game, plus that XNA Vanguard mmorpg, and probably a game based on the remnants of True Fantasy Live Online released on Xbox 2. Having 1 or 2 solid MMORPG's would be great for Microsoft's live service.