Something not available on the PS360/3DS. I also disagree about Monster Hunter, as Nintendo have already released one and have MH4 ready for the 3DS, likely we'll hear more about this in the coming weeks. In addition, Nintendo would not have announced the game so long ago if it was a joint-venture with Sony, especially as no other MH game in the series has been released on 2 different consoles at the same time.
So a new IP, but something that will sell well, and will take into account the advantages of the system. Sounds easy, no?