Unless I'm seeing some leftovers from the beta/rc, I think the default theme still ships with a nearly impossible to grab window border, which is somewhat infuriating.
http://blogs.fedoraproject.org/wp/mclasen/2010/10/09/getting...
It makes it possible to implement an easy to grab window handle in every GtkWindow regardless of whether it uses a status bar, among other things.
That one release later still suffers from blatant UI screwups like that is really disappointing.
Step 2. Stop caring that you can even resize a window by left dragging on tiny little corners.
It wouldn't matter if bottom-right resize handles were standard, but as it is only a few windows have them.