I was really skeptical of Metro until I heard a particular use case described: you have a tablet, and as a tablet you interact with it using Metro. When you're at your desk, you dock it into a station with a keyboard, mouse, and multiple full-size monitors. The monitors display the traditional Windows desktop (which you use for "serious" desktop/workstation apps), while the tablet display stays in Metro mode. So you have one system that functions both ways, which is an idea I think is pretty clever, and the complete opposite of the "multiple devices (desktop and mobile) that try to use the same interface (Metro)" model that I was envisioning previously.
Metro actually seems like a pretty good UI for mobile devices. My big complaint about it was always that Microsoft were trying to shoehorn it in where it didn't belong (desktop/workstation systems, the Xbox, etc.). It's great for touch interfaces, and IMO pretty terrible for everything else.
That having been said, this revised appearance is awful. It looks like some refugee from the ghetto of 80s/90s X Window systems. When Google showed off "Chrome OS", I thought "Wow. That looks like a third-rate, terrible copy of Windows 7", and I'm baffled that MS have decided to copy their copy. At least let me turn Aero Glass back on!