I understand the paradigm being used by not having a 'close' button, eg same as mobile phones, however what's the policy on Windows killing applications?
My concern is when Windows get's it wrong? Will it kill your main business app, that you had minimised for 30mins, just because you were at lunch and using IE, and you have a run-away instance of Flash within IE (or any other similar plugin)?
It's certainly feels like control is taken away from the user, and the OS determines what is best for the user. It's about putting the computer in control of the user and not the user in control of the computer.
I also wonder how well Metro will be received within the corporate environment? The IT dept will obviously disable Metro to give back the 'classic' UI for users (to ease migration), but a user at home gets a Win8 desktop and uses Metro and has no idea how to get back to a 'classic' desktop paradigm... It's going to lead to user confusion...
Maybe Microsoft will adopt the paradigm of separating the UI from the OS, where the UI is merely a user-replaceable shell (which it is, but it's hard to replace in Windows at the moment, opposite to the UNIX world where choice of the UI is a given). Thinking back to Win3.1, it was dead easy to replace the default UI (by editing the win.ini file and changing the shell variable), could they go back to that - offer a selection at login (which is what Solaris does, what Linux does, etc) to get Metro, "Classic" or some 3rd party add-on. We could even see KDE or GNOME become a 1st class citizen on Windows!!!
The strange thing is, it'll be very hard to offer the same UI effectively across multiple platforms. Even Intel with Meego offer different UIs for each platform despite being a single platform underneath. (They offer 3 UIs, desktop/netbook, tablet and embedded. All have similar looks and feels, but with tweaks to suite the environment which they will run).