Look at it this way, the experience of playing a song on Rock Band with friends, would that be the same if you were using normal controllers? I don't think so.
Then something like Child of Eden I found incredible playing with Kinect (sadly there haven't been more examples like it), much more so than using the controller.
certain games do benefit from not using a pad, but they are a minority imo.
obviously if you are playing a game like bowling or rock band then using a gimmicky controller helps. but those types of games are hardly at the forefront of games and are quite "basic" games.
for fps or football, i imagine it would make the whole experience worse than a pad, basically the more advanced the game is, the more you need a accurate input.
this is why some people spend £100+ on a xim so they can use specifically the mouse part of a KB and mouse setup, a gaming mouse is so accurate in a FPS it blows a controller out of the water.
people also come out and slate everyone who uses a XIM as they see it as cheating, personally i think that console developers should learn from XIM and add more accurate inputs into their consoles. this doesnt mean make move/kinect more accurate, it means either make the thumbsticks more sensitive and accurate or add kb and mouse functionality to the console for all games.
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