There are two things about this that really makes me doubt MS will a tablet style controller.
The first is, with their big push for Kinect to be how you control things, why suddenly make a controller that is more involved than a traditional controller, and takes away the focus from Kinect.
Also, I'm pretty sure MS would have figured out how the controller would be for the next Xbox before Nintendo showed off the Wii U. I don't think they would suddenly change to that kind of controller after seeing Nintendo show it off, especially with the negative reactions I've seen to the Wii U controller.