It will apparently ditch the tilt motor seen in the current Kinect, as the larger field of view should accommodate most play spaces. For example, the new Kinect should be able to detect a 6' tall person at just over five feet from the television. As previous reports have suggested, it will also be able to recognize more minute details, such as whether a hand is open or closed.
For what it's worth, in the absence of verification, the tech wizards at Digital Foundry find the leak plausible, though it may not be the most current information. Furthermore, the information does seem to match up with previous reports, specifically the sensor's improved resolution and its ability to detect much finer details.