That would have been far preferable.
This is thing that annoys me off about the whole idea of Metro: it's behind the curve on multiple levels.
First off, the whole forced full screen nonsense is trying to "Me too! Me too!" iOS from 4 years ago.
Secondly: those that already have been doing tablet UI's are realizing that the tablet UI needs to evolve and become more like the desktop, NOT the other way around which is f'ing assbackwards.
IE: Samsung for example, currently has the first iterations of multi-window on the Galaxy Note tablets and phone. If you have enough screen real estate, there's no logic to not allowing multiple windows if the user so chooses. Touch interfaces DO NOT mean people's brains become more simplified and that they can't possibly be able to multitask.
Even on a tablet, forced-full screen will eventually become a past-limitation. On a desktop- it's BEYOND assbackward, it's downright stupid.
And for those that say Apple is doing the same thing- I submit you probably haven't used a Mac with a touch interface. Apple's thinking on touch interfaces is lightyears ahead of MS's backwardness. Launchpad on Mac OSX makes perfect sense; it doesn't try to take over the OS, you call it up with a gesture and it then becomes a very logical way of launching apps. There's no need to make it a forced default. You can touch any menu and pull it down the same as you can with a mouse- again, logical. Your brain doesn't shut down simply because apps have multiple windows- they work the same way as multiple windows always have. Apple did the obvious: made what already works fine work with touch as well as with point devices. They haven't tried to turn OSX into iOS. Sure, iOS and OSX will eventually merge, but Apple is smart enough to make it work so that it seamlessly works logically with both.
MS - late the party and blundering around not really knowing what they were doing- thought it would be speediest just to crudely staple the tablet interface over the desktop and then use rubber bands and scotch tape to kinda-sorta hold them together. In their haste, it didn't occur to them to simply make the traditional desktop interface more touch-friendly as Apple has done, and make Metro more of a gesture-driven launcher that you only need when on a tablet or touchscreen device. That would have actually required some more talented devs who are more up on modern UI design.