So, since the games are becoming more focused on the visual flair as time goes by, wouldn't it be nice to add this into the game?
Remember in Shogun 1, where you had a throne room? Imagine bringing that back, but, adding a trophy room, where you have the crown of that empire, or the statue of that god you stole from an rival empire etc. Sort of like the Assyrians did in ancient times. Beating a Roman Army and stealing their Eagle Standard etc. This too could have an effect on foreign diplomats coming to discuss business.
Also, instead of just having a record of epic battles, provinces lost etc, they could program an algoritm with different sets of pieces (heads, death, battles, taking cities etc etc), that together form your people's story on a wall mural or something
It doesn't have to be specifically those things, but I like things that give more immersion to what's happening. Like remember Rome 1 where everyone got different traits based on how that had acted in the field and campaign map? My 0 star commander talking about how he rather go home to mommy and eat dessert than to fight in the battle in his battle speech. I love those small things.