An option to toggle off wonders/wonder age like with the titans. Any time a game adds a major game-changing element, it should be made optional.
Female pharaoh models. It’s a little silly to have a male pharaoh named Cleopatra.
Culturally specific regent models. The generic sword-and-sandal aesthetic of the regent doesn’t work for every civ now that the game is incorporating East Asian and American mythologies. It would be especially jarring to see a guy in a metal breastplate in an Aztec setting. Age of Empires 2 has regional variants for the king in regency mode, so there’s no reason AoM can’t.
Bring back the unique Asian wildlife introduced in Tale of the Dragon. It’s ridiculous to have multiple tiger myth units but no regular tigers. I had assumed the devs were saving these animals for a future Indian expansion, but I doubt it now that asuras have been incorporated as a Japanese myth unit (though why Shinto is fair game but Hinduism isn’t, I’m not sure). I wouldn’t want the existing Chinese maps to change, but a map based on South China or Vietnam would be a cool way to reincorporate them.