That's like saying that Rift is just another VR. It is but it's so much better that makes it actually usable. Same goes for Leap Motion. There were cyber gloves in the 80s/90s, now there is Kinect but LM is the first motion tracker that has fidelity and response needed.
It's very simple and small, which means that it can be integrated in current version of Rift. That may become an issue if Facebook find a way how to make Rift significantly smaller but I bet this thing can be simplified further.
To become full VR experience, Rift needs full head tracking capability (needs another camera at the back) and needs motion tracker. Maybe even different design so it can be used as reality augmentation device and not just closed virtual reality headset.
