Ok, ill try summarize weak points in AI behavior:
1. Often civic changes, especially in late game. I had Deganawida enter anarchy for 17 years, then 15 or so years no change, then he changes civics AGAIN for 13 years this time. Happens often with many other leaders too. Those values weighing need to enter revolution needs to be recalculated.
2. In some cases AI doesn't properly attack cities. I have Deganawida (who successfully conquered entire North America, wiping Native Americans and Aztec) with his stack of 160 riflemen, 100 mortars, 100+ ribaldequins etc. standing at Maya city of Mutal for 30+ turns, it seems he tries lower its defence (had 265% at max) with frigates 2-3 at a time, and not using mortars for some reason for bombarding (he had some heavy cannons too). Troops defending Mutal are 2 (two!) guards, str 9 ones.
Another issue - when i try to select Nautilus in building queue (i built Nemo wonder) - i get CTD the moment i click it.