Got up at a horrid time to give this a whirl before work. Played as Aztec for around 100 turns and have the following feedback.
UI: really don't like the UI of the cities, I prefer the CiV interface where you click on a city and can undertake all the functions rather than having to cycle through different actions (need to click on city and them click move worked button).
Bugs: the AI valuing great works as worthless is still in the game (bought a great works from England for 1gc - 4c +8t/pt).
The eureka moments seem to be a lot harder then what I saw in the streams. Maybe I just suck, but my start was without hills, mountains and rice and most of the game I struggled to optimize my research, had to research quite a few techs without eurekas.
The AI didn't really do much of anything so far in my game, saw France loose a horrific amount of troops trying to take a city state.
I know the above sound negative, but first feeling of the game is actually positive. I love the builder change, and imo I really felt like having so many options to choose from (builders, traders, settlers, districts). Having genuine choices is a sign of a good game.
Seems like earlg war against city states might also be a powerful strategy.