What is the enhancement in mind? How should it look and feel?
It should look and feel just like the old set editing capability.

Previously CG was able to edit sets. This was incredibly useful for sets which replace only certain items from the current set (e.g. I have a "main" set, which is my holy gear. I then have a set which swaps in the few DPS items I have. I then have a third which is my "boss" set which swaps in some hit items. This prevents me needing to update 3 different sets every time i get an upgrade (I rarely need to use a different weapon, for example). Now if I want to update one of the sets i need to go through and unselect most of the item slots (plus remembering which ones need to be unticked).

Another use for set editing was for updating an off-set when you aren't wearing it. Now to update the set I have to go to the bank, equip the old set, swap the item, make a new set, swap back to my old set then bank the whole thing again.

Losing both of these make using the addon a lot more trouble than it needs to be.