The best idea for a end game Green would be an Item made for your charater called the (insert character name here). This item would have a Skin of players choice from all skins available from all the combined games. Comes customized already and a replica is placed in your personal Monument.
It would be nice to get a green item that can be inscriptable.
Make it that you can't destroy the item and you would have to overwrite the inscriptions. How about making them completely customizable?
Selectable skin
Selectable color(s)
Selectable damage type: (make it so that it is very specific to a chars needs)
example sword type holy damage 15-22 req 9 water
example staff type dark damage 11-22 req 9 strength
example bow type lightning damage req 9 channeling
Unique modifiers that you don't normally see:
how about a sword with +1 to earth (20%)?
how about a staff with +1 to strength?
Also introduce new "unique" inscriptions to the items; such as:
+15% damage (while under the effect of a shout) (maybe max that at 10%)
All examples of course but maybe make them truly unique.