They should have called it 'Window' 8, not Windows, as single apps seem to take up the whole window when they are running. Maybe this can be changed, but I always thought the whole point of Windows was that you could multitask.
More seriously, they really should have built two OS - one for tablets, the other for desktop PCs. Instead, we have this hybrid piece of crap. I've not found the Metro interface to be at all useful for work requiring a keyboard and mouse (i.e. 99.99% of the work I do on my desktop) - all Metro does is appear from time to time when I don't really want it to (e.g. if I hit the Start button, do a search, accidentally click on the side or corner of the screen, or open a file that, unbeknownst to me, is associated with an app instead of a desktop program). Usually at that point, I panic momentarily before looking around for an 'X' to get rid of this thing that has suddenly taken control of my entire screen. Eventually I remember that alt-F4 does the trick.
If I could have my way, I'd remove Metro and keep everything else. Apparently the OS itself is quite an improvement over 7, but the UI sucks balls.
Maybe I am old-fashioned but I don't think tablets will ever replace desktops entirely. Sure, they have replaced many of the functions that desktops have previously performed, because they do these things better. But I can't see myself, or anyone else really, comfortably writing reports or working with spreadsheets or multimedia on a touchscreen based system anytime soon. (A tablet with a keyboard is just another laptop.)
How to make Windows 8 look like Windows 7
I think they're a chance to replace PCs (for most purposes) eventually, but only by becoming fully dockable so you can use a keyboard/mouse/monitor/etc the same way you can with laptops today.