If you don’t want to watch smth on YT, and avoid the click:

• Advisor movies (I, of course, wholeheartedly agree)
• Palace Screen (I know this was one of my favourite things as a kid - even though it is completely superfluous)
• Changing leader art (i.e. Outfits and such change with tech progress)
• Joining Great People to cities (Like in Civ IV)
• Hotseat Multiplayer (It may seem obsolete nowadays, but I genuinely think it does add a nice, more communal kind of MP where you don’t have to bring your PCs like in a LAN)
• Keyboard movement
• Bigger maps
• Release the games when I was 10 (instead of when being a sad adult)