There's no point in changing up the controller, many more buttons and things would start to become too confusing, right now we have up to 20 interactive button presses on the current pad (4 shoulder, 4 face, 2 thumbstick clicks, 8 D-pad directions plus the start and back buttons), that is a lot and can be very confusing at times.
There is no question that innovation in game control is, if not 'necessary', at least valuable and something that should be explored, and we are getting that with the Kinect, the smart glass and, outside of Xbox, the Occulus Rift.
The control pad was created to be an easily manageable device that let us have as much control over our digital characters as necessary, a few generations ago it was fine, but as the generations have moved on, gaming experiences have become more personal, we have been granted a wider range of activities and larger worlds within which to do them. The pad still suffices for a lot of things, but the innovation now needs to be outside of the control pad, something as well as, to do things that improve the experience that either the pad just can't do, or at the very least, the things pads CAN do, but do them better. I can pause games and command allied AI around via the pad, but it would be so much easier to use Kinect and say ;Garrus, flank left, Ashleigh use grenade' and have them do it, it would keep the game flowing and keep me in control.
The Smart Glass is already being used, commander mode in BF4 and however it is used in the Division, DR3. It does appear a little gimmicky right now, but in time it could be a very useful thing. Plenty of people have talked up the idea of using the smart glass as a pip boy for example, I like the idea of playing a game like GTA where by using the smart glass app on your phone, the game phones you on your phone and you listen to the conversation there instead. It is, without question a gimmicky idea, but I love the prospect that the smart glass can improve immersion in experiences.
The other new piece of tech I'd love to see adapted is the google glass, maybe not that one specifically, but the damn thing looks remarkably like this eye piece Garrus has in this picture from an article on this very site http://www.oxm.co.uk/38274/features/mas ... -and-more/
The prospect of playing something like ME with something like the google glass and have communications from EDI through the ear piece and information through the lens part, an augmented reality experience.
I guess my point is that, unless you start throwing more buttons on the thing, pads have pretty much reached their limits, so now it is time to look outside of the pad to other options, remove control from the pad where it can be utilized better on other peripherals and streamline what the pad can do instead.
This however brings up another concern, and the one which I think is the real reason why MS haven't changed all that much here, a lot of people just aren't interested, and worse, vehemently against the idea of interacting with game in any other fashion than their beloved control pad. Making Kinect standard kit is a good start to getting people involved, but there will always be luddites who aggressively fight against it. Not changing the pad too much was the one smart PR move MS made, whatever other problems people have with them, they still know that their beloved Xbox pad hasn't really changed.