I second the import of Blender Files, but FBX would be ok, caus Blender can export FBX that are small than native Blender files.

For WED, i would see lot more the abilty to simply and quickly create our own panel in WED that we could activate / de actiavte or install/remove (somewhat like in Unity 3D) !
For example some people could create their own panel inside Wed for their game tools (special AI management, special Dungeon kit pieces alignment , own custom entities and attributes management etc ... etc ...)

It's just some idea !