This is indeed sounding like a copy of Nintendo, not even a different approach like Kinect was. Not like I didn't already expect it. The current MS approach is multiplatform. A bridge between XBox and Surface is obvious. They could have an advantage in the fact their tablet would probably still be a portable tablet, but would they put on physical game triggers as well?
What I doubt is that it will be out before the 720. That would in fact be foolish, they are already behind Nintendo's curve, they should hold back copying them until they discover the flaws in Nintendo's device.