I agree that the current suite of Metro apps is crap, but that hardly makes the OS a mess. I've been using it as my primary OS for about 6 months and my usage hasn't really changed from Win7. All my work is done from the desktop, with the new start screen working as a useful short cut organiser.
Multitasking is boned
Not sure what you mean there.
...it works badly with multi monitors.
Depends on your definition of 'works badly'. I think they've made smart choices. You can easily nominate which monitor is your Start Screen monitor and all Metro apps will launch there. You can't seem to run metro apps on more than one screen, but you can have 2 visible on the same screen using docking.
Try running multiple metro remote desktops on two different monitors. You can't.
Metro apps are not made for multiple screens and this is what they are pushing for as future software. All full screen tabs.
There us a lot of hot corner action that is painful when those hot corners are in between the two monitors. I had to offset the screens so I could catch the mouse to hit the start button area.
