The biggest problem with the Kinect is... kind of hard to get around. Its 'buttonless gaming'. Theres a lot they can do with the voice recognition, face mapping, body movement, but... without buttons, making conventional video games is going to be hard without a control stick for movement. Theres a reason its only had party games and on rails shooters.
I'm sure they COULD work out a traditional game, like Fable 3 or Halo or whatever without resorted to retarded stuff like 'lean left to move left' but like the Wii, they may decide its just easier to play it safe and stick to the cash cow sports compilations.