Wee problem: Kinect is sloppy - just like Wii. So while it's still an evolution, it's a lateral mutation rather than an advance for the species. Further to that analogy, Darwin might suggest it will only keep on living and maybe even thrive if its unique new features don't prove a detriment in the eat or be eaten ecology of videogames.
The good news: It'll probably thrive. Someday.
As of today, Kinect comes off as rushed.