Allow 'code folding' for rules in the .cga editor.
In the 'Inspector' window it would be good to be able to collapse/expand on the 'Group' name. This would be useful for when there are a lot of attributes under different group names.
Be able to group layers in the 'Scene' window.
Better snapping - snap to generated models, not just the base shapes.
When you import a CGA rule from a different CGA file it would be useful if it was then added to the automatic code completion suggestions.