In the game it was stated more than once that Astarion really misses his appearance, that he hasn’t seen himself for over 300 years. The game provides us with an opportunity to grant this wish, but there is no reaction to this opportunity from anyone including him. I'm talking about the artist quest, in the end of which said artist offers to draw us a portrait. It seems to me that it would be nice to have one of Tav's dialogue options suggest drawing Astarion instead of them, and for Astarion to have at least some reaction to that. Or even a separate dialogue because it is so important to him.
Even if the portrait is drawn with Astarion as the main player character, nothing happens. His “portrait” simply lies in the inventory and is never mentioned again.