Given the success of Exposé, perhaps we have given up too early on non-overlapping window GUIs?
For example, suppose you combine the automatic layout of Exposé with different zoom levels and win 7's dock. Could that provide something workable that would do away with overlapping windows?
You could provide Exposé on a per app level as well. Just click the app's icon and you will see all its open windows all on the screen at once with no overlap.
If you want to see a certain subset of windows on the screen at once, just click on all of those in the subset to zoom in to only those windows, again with no overlap.
http://awesome.naquadah.org/ http://www.nongnu.org/stumpwm/ http://xmonad.org/
or am I just confused?