1. Ais need to consider the Millitary strenght of there Neighbours and to be aware of an DoW.
2. Culture/Tourismus focused Ais need to focus more on Great Works and Digsides.
3. Portugal needs to build Feitorias.
4. Arabia needs to use his doubled Luxurys.
5. Babylon should plant there first Sientiest and not waste it for 1 free tech..
6. Byzanz should focus more on Religion on many games she doesnt even get one..
7. China doesnt double attack with her Unique unit.
8. Venice should consider Puppets more often durring the mid game instead of playing Yolo 1 City challange.
1. I never see an AI without at least 5 units in my game (I play on emperor) but same goes for when I have played King and Prince.
2. I see AIs always digging sites and getting great works from them, though I don't think they swap them or use the bonuses they could get out of them (I could be wrong, haven't played a culture game in a while).
3. I see her build them a lot, but if she is at war she probably wont. I don't think AIs have the taste to run a couple workers all around the globe.
4. He failed in my last game, but still had a bunch of luxury copies, so I'm pretty sure he build the UB.
5. I agree here
6. In my games she usually does, and she will on higher difficulties with the AIs bonuses. (King and higher). Though, since religion is not a victory condition, the AI might be focusing on other things.
7. Yeah, I don't think I've seen her double attack with it.
8. I've seen Venice puppet like crazy on all different levels, but it could just be a coincidence.
Try playing a few more games to see if these issues still happen. If they do, I would raise the difficulty to King (it would iron a lot of this out for you).