This is not a gameplay feature but I wish that they would bring back era soundtracks like they did for civ 4. Basically each era had its own unique soundtrack and each civ also had its own soundtrack for each era along with which ruler lead their civ.
I enjoy Civ 6 alot but imo it was not nearly addictive as 4 and 5. Many people I've talked to said Civ 6 is the best one yet based on its straightforward simplicity. I personally loved the micro management of the previous ones. Sure its a bit more involved and difficult but there's more to do