99% of the people who would want this, are people looking for an easy way to create the mmo stile gui. If you make the plug ins mainly work to control the mmo ui example, this would be an excellent start.
Big idea would be to set up easy depth for each element from camera. Another would be to make it work with 3d cameras not just orthographic ones.
Have a new window available for on-screen placement of static gui elements, kinda like the mini camera that shows what the camera can see, where you can drag elements from the SWF to locations and it shows up there at run time. {resolution independent} (a small grid would work, 3x3)
Im just wishing and dreaming...