I have no clue.. I do know it'll most likely come from Nintendo though.. I mean look at Wii MotionPlus.. It seems to be a big upgrade but it was how Nintendo wanted the Wii Remote to be in the first place so really you have to think about what 5 years of Nintendo R&D could do on top of the Wii Remote, Wii MotionPlus and the Nunchuk.
Sony haven't changed their controller design since they copied the N64 analog stick and decided to add two for symmetry purposes. It's stayed the same.. I know some people will say well yeah, they got it right the first time and sadly I think Sony think that way too.. I just can't see them innovating too much in terms of controller design.. I could see some kind of split controller though.
Microsoft could really change it up but I think they'll screw up if they change their controller too much. Microsoft are very good at perfecting something that somebody else has made so if they go for a Wii Remote like design I think they could do very well but they'll be a generation behind Nintendo.
Who knows what may lie ahead.. I think we should hear the first things of the next XBOX from Microsoft next year, whether it be a unveiling or just a tease that they're working on games for the next generation or something.. So it won't be long until we see some next gen goodness
