AI got dumb.

[Commander Bello]

Playing with these settings:
Monarch, giant map, only 14 nations, normal speed, revolutions on, minor nations, no tech brokering, agressive AI, raging barbs, barbarian civs on, tech diffusion on

I have not met the described problems with AI being slowed down. In fact, in my current game they are doing a hell of a job in spreading and have had big cities from the beginning on.

Seems to me that the limiting factor is the space they have in the beginning to spread.
Actually, I very much love my current settings, as it is hard to fight the barbarians, and when you are done with that, you find some opponents worth to be fought.

 

[Arkatakor]

Playing with these settings:
Monarch, giant map, only 14 nations, normal speed, revolutions on, minor nations, no tech brokering, agressive AI, raging barbs, barbarian civs on, tech diffusion on

I have not met the described problems with AI being slowed down. In fact, in my current game they are doing a hell of a job in spreading and have had big cities from the beginning on.

Seems to me that the limiting factor is the space they have in the beginning to spread.
Actually, I very much love my current settings, as it is hard to fight the barbarians, and when you are done with that, you find some opponents worth to be fought.

I play monarch, huge, epic, tech diffusion on, revolutions off. I can confirm that the AI are dumb, not only when it comes to slavery (having size 3 capital cities when mine are 12+) but also in military tactics. When they DoW on me, even if they have a mightier army I am just not concerned at all.

Its gotten to a point where neighbors who have a border stretching the length at least 5 cities DoW on me, nothing happens after that, and I forget that I am at war with them, say 100 turns later. Then I notice the 2 swords in the leader info screen.

 

[Carwyn]

Strange, we don't have that problem at all! However, we did mess with the civics and turn tech trading off. One thing we did was to remove all weighting for civics choices and rebalance them a bit. Unfortunately, I didn't do it and am not sure what was done, but the AI are HARD in our games!

Some of the returns on tile improvements are changed too to make them a bit richer.

We play at Monarch, Large or Huge, with revolutions on and barb civs on, tech trading off and no random events.

Edit: version 2.71 with Afforess' modmods.