There's obviously some copying of Nintendo's Wii U going on here, but there's also some copying from Apple too.
Microsoft is finally starting to see all their different offerings as part of one universe, and they're trying to make sure that everything -- desktop PCs, mobile phones, tablets, and XBOX 360 -- can be interconnected within the Microsoft ecosystem. Granted, if they had done this earlier, we wouldn't be talking about Apple in the way that we do.
To be honest, this has been one of Sony's biggest failings as well. They have televisions, radios, game systems, and music and movie studios, but they haven't always worked together. Up until recently, there hasn't been any advantage to watching a Sony movie on a Sony TV, and even now, the advantages are largely undone by all the DRM and restrictions that Sony places on their content. If I rent a movie from the PlayStation store, why can't I watch it on my Bravia TV, PS3, PSP or PS Vita?
Anyways, I suspect that going forward, everything that Microsoft does will link to something that they're already doing. And it will be all Metro all the time.