There is some good stuff under the covers, from a programming perspective. However, I think the design language of Metro is too restrictive for the desktop. I like to think of the problem as the three little bears of UI. The WinForms bed was too small, it was difficult to make applications that looked distinct. While the WFP bed was too big, promoting applications to look like anything the programmers dreamed -- plus a little scoop of ugly butter. Metro was a good set of guidelines for the phone, when space is at a premium, but becomes too restrictive as precision of the user input increases. What needs to be created, IMHO, is a design language that scale up and down the precision of controller to optimally complete a given task when presented with the constants of the interface. Or something along those lines.
That's a great analogy, and I completely agree. I have seen nothing to indicate Metro scales well to larger displays or more complex apps at all. The massive visual (and usability) shock when you invoke Metro by just calling a search from the standard desktop is very jarring and is just very poor design.
And..."beautiful"? Really? Metro can be beautiful, but I haven't seen much evidence yet in Win8. On a small touch display, monochromatic icons and huge fonts are fine - you need to see info quickly and from a good distance from your eyes.
But blow that up to a 23" display, and it really starts to look as if was designed by Crayola - and that's the good stuff, the tiles that were designed from the outset for Metro. Seen the metro start screen after you add an app? Separate, mono chromatic square with small, ugly old icon.
Especially with the bastardized Aero they've got going - that is truly the ugliest GUI MS have put out in recent memory.
The problem with MS and GUI's really comes down to fit and finish. Some concepts are good and somtimes - like with the Zune player - they do show attention to the details. But it's rare. You can not like Apple's designs, but you can't argue that one of the reasons so many people find their interfaces attractive is that spend a lot of time on the little details - font rendering accuracy, drop shadows, slightly curved edges, smooth backgrounds that don't clash with the foreground elements, detailed icons, etc. MS has never shown that attention to detail and so far they don't appear to be starting now (I mean really, a bright-green monochromatic background is the new Metro design guide? Really?).
There's of course time for tweaks, but some of the visual problems go deeper than needing a nudge - and again, MS seems to be leaving GUI design to the last element instead of having a culture of design from the outset - which I think it needs.