@Greenfire your post does meet the 2 most important conditions where most of the player base would agree on:
- It doesn't break game balance (cosmetic only)
- Available to everyone who contributes to the goals set
It's up to the Devs if they would include D-gold as a possible reward, although LOTRO, for example, gives already shop gold in smaller amount by completing deeds. So it has been done before and possibly doesn't break the monetisation of the game.
Well thought, I like it !