Hey Paradox! Why don't you tie city graphics to province culture as was the case in CK2?
Not only does it present more information to the player (who would no longer have to go to the cultural map to confirm that Athens has indeed become Turkish), but it would be more immersive and realistic. The idea of massive cities suddenly changing appearance after conquest by another faction is very ridiculous.
Also, given that this features in CK2, it seems very doable.