Yeah would be good. They did it so that apps can be scaled properly. Between all the screen sizes win8 allows so it all runs smoothly and developers don't have to test a thousand combinations. So at least there's a reason for it.
I like that a lot, so I guess if they can do that kinda thing on tablets, perhaps similar styled, though not being able to screen share ( mobile screen to small obviously) but switch between apps like that, ( pulling them from the side of the screen).

