It will be able to track players with a height of one meter, feature a mode for both seated and standing players, detect hand states (such as open or closed), as well as extra and rotated joints.
Apparently it will also be able to track six rather than two active players, occluded joints, and sideways poses.
Under the bonnet is an improved field of view, resulting in much larger play space. The RGB stream will have higher quality and higher resolution as will the depth stream which should be able to resolve much smaller objects.
An active infrared stream permits lighting independent processing and feature recognition and it will be faster with pipeline latency improved by 33ms.
There is a lack of a tilt motor which is probably to make it a bit cheaper to make.
What is the most important feature is the USB 3.0 cable which will help the new version of Kinect make super fast transfers.
The leak appears to coincide with Sony's PS4 announcement and is probably a spoiler.