I think it's cool and has potential, but I also think it's more proof of concept. MS isn't really in the Music/DJ software business, there are plenty of companies that are and if those such as Traktor / Serato made a Windows 8 app that uses the remix cover, that would be amazing.
Not only amazing, but encourages software dev's to embrace Windows 8/RT. So I can see a situation where custom covers can be ordered by companies/devs. Loads of potential there!
But whilst I think that's true, it may never happen. Anyone remember
SideShow? Huge potential, but no one supported it. So what really needs to happen is, the next generation of Touch Cover needs to have eInk. So
anyone can make an app with it's own 'virtual cover'.
If they did that, they could truly realise, or at least get closer to, the
Courier vision.