In a nutshell, the problem with Metro is that while I personally think it is by far the best-looking and most elegant of the current crop of graphical user interfaces (iOS, Android, Window 7, Mac OS X, GNOME, KDE - they all feel outdated and archaic compared to Metro), it's not suited for complex arrays of buttons and menus. This poses problems for complex applications like Office, Visual Studio, Photoshop, and so on.
However, Metro is the future; it's not just the tablet interface - it's the interface Microsoft expects us to use on desktops and laptops as well. The Windows 7 desktop in Windows 8 is legacy; it's being phased out and has no future. This means Microsoft must demonstrate that Metro is suitable for large and complex applications like Office. As it turns out, the company itself is having problems with it as well.
"The large metro style interface is designed for [...] touch. It doesn't necessarily scale incredibly and in an obvious way over to a highly dense environment. Take Office, Visual Studio or other experiences," Kaneko told The Verge, "So there is an awful lot of work to take the principles of Metro [...] and make that translate in an authentic way for different experiences that have different interaction models, that have to accomodate different detailed input methods."
"If we can strip out what we call chrome in an interface then your content becomes hero. philosphically we love that idea, and you see it manifest in [Xbox360, Widows Phone, Windows 8]," Kaneko further added, "Challenge is, chrome actually performs a functional role too and has always. It helps us group similar tasks and create visual hierarchy in a very dense space."
Sadly, the interview doesn't touch upon what I really think is going to be the problem. You see, I'm pretty sure Microsoft will eventually be able to create a Metro interface for Office that doesn't cut too many of the features people have come to expect. No, the real problem is that in its current incarnation, Metro in Windows 8 has virtually no window management.
I'm incredibly curious how Microsoft is - if at all - going to address this. I love Metro, and I'd love to use it as my main interface - but not in its current incarnation. It's going to need more consideration for us folk who work on our PCs.