Not a big priority at all, but it could be a nice addition for a bit of immersion (after all most TW mechanics are there for this)
You know how you can rename cities as a player ? I suggest there was something so in some instance whenever a given culture conquers/build some cities, they rename it in case of the AI or prompt the player to do it. Would allows both a bit of loreful element of reconquista for dwarfs vs GS or lizarmen vs skaven and a bit of cheesy elements from the baddies conquests, like DE giving corny names to some of the HE settlements, same for the Bretonnians with southlands cities etc.
Behind the scenes it would be quite simple : add a table for "suggested settlement names" linking a settlement id, a culture and a name. Whenever a settlement is captured or rebuild, the game checks if there is a suggested name and changes it.
Since there is a table, obsessive modders will be able to extend it as much as they want beyond the basic changes.