The Geometry Browser could be an extremely powerful tool for MGED, especially since a bulk of new users are looking for more GUI functions and less commandline useage.
Some ideas for Geometry Browser:
1) Drag and Drop movement of combs/regions/solids
2) Copy/Paste instancing.
3) Right-Click menu consisting of:
a) Display / Hide
b) Wireframe / Shaded
c) Display Color
d) push / xpush
f) All Applicable Edit Menu Commands (Translate, Rotate, Move V, etc)
4) When any object is left-clicked, all the attributes are displayed in an easily edited area of the Geometry Browser window.