IllumiRoom is probably an add-on for the console just like Kinect is for the 360. I doubt it will be sold from launch day on.
It will be expensive and not supported by every game (sure, every first party game and quite a bunch of 3rd party games, just like the "better with Kinect" titles)
It might even work with some Movies / TV series, especially the ones MS is rumored to produce (Heroes).
I will gladly pay for it, because out of all the stuff we have seen from the PS4 and the Wii U, this is the only feature that really feels fresh and new for the next gen. The Wii U is a gaming console controlled with a tablet and the PS4 is a more powerful PS3. And so far, the rumor indicates that the Xbox 720 will be a more powerful Xbox 360. This is not a bad thing, but something special is missing so far. IllumiRoom could be it. Imagine showing it off to your friends. It certainly comes with this wow-moment and knows how to impress.
Imagine not having GamePass on your console...
