I think the only real concern for me to have is
Would developers try to use the controller features the wrong way instead of focusing on just making good games. Just look at the PS-Vita which has perfectly capable controls and the impressive processing hardware to give PS3 like games in a hand-held system.
However, so far developers just can't resist ruining some part of otherwise good game by injecting in forced controls that don't work. In other cases they spent time and effort on alternative controls that are not desirable to use over traditional methods.
The Wii had the same problem but not as much the developers fault as the standard Wii remote + nunchuk just didn't have the right layout for traditional controls. Only games designed for it had a chance of playing well while ports from PS2, PS3, X360 game designs would have alternative motion controls that generally sucked.
Touch controls work great... for games specifically designed for it (Plants vs. Zombies, Angry Birds, etc)
Motion controls work great... for games specifically designed for it (Wii Sports, Sports Champions, Kinect Sports, Skyward Sword, Red Steel 2, etc)
Traditional dual-analog with lots of buttons controls work exceptionally well... for most game designs popular today
