I know not everybody like/use Exposé, but I thought it *could* be useful. There was skippy, a third party app which used to do that, but it seems quite dead now. I'm not sure if a non-GL exposé is really useful, but as xfwm4 don't have GL compositing (and don't intend to, I guess?)...
This is a pure wishlist bug, just in case :)
This report is actually a duplicate of #3541.
*** This bug has been marked as a duplicate of bug 3541 ***