While being a great expansion, I have noticed some things that I would like to point out and see if anyone else has noticed these and also do tell if you have noticed some other stuff related.
1. Happiness seems to be much easier to control the longer the game goes, with the combination of powerful policies like protectionism, humanism, order tree and religion + wonders like Eiffel Tower. I often had 40-70 happiness in Emperor all the while spamming colonies as Spain, just because I could.
2. I also seem to get consistently tons of gold after renaissance. In all my games I have gotten around 250 - 400 gold per turn on emperor and I'm not a master in this game. Is this a lot of gold or normal? Seems like a lot to me. Might just be my style since I usually go for commerce (but I don't spam trading posts, usually farms and mines and occassional trading post.
3. Also AI seems to lose a lot of ground the more the game progresses. I struggle in starts with challenging AI on emperor but on REN-IND I become too much of a economic powerhouse that the AI can't handle. I overwhelm them later on with my science, gpt and production. Can AI handle the late game well enough? Does it build factories asap and production boosting buildings? Or does it keep building mediocre units most of the game with low production and not utilize the gold well enough?
4. Some AIs seem to get totally paralyzed and won't even improve their capitals improvements such as stones and other. I captured Egypt's capital on Emperor and it was the saddes capital I've seen in a while, something that I expected to see in 2000 BC when in fact it was 800 AD.