If you want to do two things at once in metro you just need to dock a metro app to one side of the screen. Want to game and read a walkthrough or watch a tutorial? Dock metro IE to one side and open your game.
I want to do 3 things. Even 4 things. With this monstrosity called Metro, I can only do 2 things at a time.
Example, I generally have 2 IM programs, one browser, one media player (with either videos or music) open on my desktop. I also keep other programs open, but minimized, and bring them up when I need them (while keeping everything else open on the desktop). This is IMPOSSIBLE in Metro. Now, you may say that most programs out there are non metro, which means they run on the classic desktop. But that scenario only holds true at this point in time. With Microsoft being all bull headed with Metro, more and more apps will be Metro exclusive, making the classic desktop redundant.
So you see? Metro is very limited. It is fine for some, but not everyone. With the old Start Menu way, everyone was happy. Also, almost no one is asking them to ditch Metro completely. We are asking for choice. Keep Metro, but also provide the option to easily and completely disable it.
Microsoft is being really stupid and arrogant about this whole Metro business especially considering their size and market share.