Terra - Huge - 4 to 6 Starting civs. These are my best settings for revolution.
That was my choice for a long time. Just start with four to six of the ancient civs every game (Egypt etc etc) and then watch the others spawn. You then have some traceability and can see how the ancient civs progress compared to the spawned civs. I'm currently doing twelve nations on a huge Terra map to start out with on aggressive ai. I kinda like the chance for a bit of crowding early on....
Aggressive ai has to be an important consideration for one fact. Corporations. Once you learn how to manage corporations, the human player has a huge advantage over the AI late game because of corporate resource trading the AI doesn't fully comprehend. With aggressive AI turned on, the AI is generally more difficult to trade with. This makes the hoarding of corporate friendly resources difficult to achieve because the AI's are simply less likely to trade because of their uncooperative approach to diplomacy. Thus the benefits of corporations are significantly more difficult for the human to exploit.
Aggressive ai has to be an important consideration for another reason. The space race. I think late game the ai's are just not real good at organising the space race compared to a human. However with aggressive ai on, the AI is generally very well prepared militarily if it needs to use it. The military pressures are so high, that it forces the human to have to divert production to military just for the sake of the *potential* for war. Thus the space race too is more difficult for the human to pull off and is more time consuming. Also, armies are expensive and this makes the end game just more difficult generally. I'm referring to Monarch level.
From my perspective, the main weakness of the AI is late game strategy. If I can make it more difficult for the human late game compared to the AI, that leads to better games....
Aggressive AI is a pretty good option. Sometimes all it actually means is that a civ might have a bit more tendancy to declare on you. However often on the higher difficulty levels when the human is pushed to the limit on defense during the midgame, the AI does very well having a little bit extra tendancy to attack.
The main drawback of aggressive AI could be culture and domestic stability under Revolutions. I'm not 100% whether an AI will still attempt a culture win on aggressive AI. I think so but not sure. Culture is an important aspect for the AI to create stable large civs under Revolutions.
Definetly I can say that on aggressive AI the the AI will still go for a wonder victory, building cultural wonders for the sake of their magnificence. Now that is not overtly "aggressive" so it's a good sign for the aggressive ai option I think.
Whatever, plenty of chaos is fun.
Keep in mind that I don't play a lot of civ (yeah right!!!).....
I only roughly finish four games to the end each year (that's roughly 300-400 hours of play per year and two to three months per game). I basically try every which way I know how to win on Monarch no matter what the starting position is (that is probably impossible and tundra starts aren't much fun!) Never give up if you are in the top ten nations. Once the late game starts, you can catch up quite a few places. First place is the goal of course.
Cheers
PS) another great option is random personalities. After a while playing civ, it becomes more fun to try and second guess a leaders personality from their behaviour rather than know what it is straight up. Surprisingly, random personalities doesn't seem to detract too much from the AI's strength, and sometime by fluke, can make an AI very strong, stronger than vanilla.