What do you suggest for AI aggression level in the future? I think I had it maxed out this game which was another(I know, again) big mistake for my game play style on Regent in archipelago.
Aggression level doesn't really matter much, imo, in regards to difficulty. In fact, a maxed aggression level actually might give you an advantage - it makes the AI more predictable. Know how your enemy will react is a positive.
Not too long ago I revisited SID, just taking a peek, and ended up with the Zulu, Aztec, and China (I think China) on my border, along with France. Aggression was great. Everyone was fighting everyone, so I could pick two cities from one civ, take 'em, then take two from the next, and so on. Only civ giving me trouble was France, who were harassing my exposed resource cities way out in no-man's land. Turned out to be one of the easiest SIDs I've played - I didn't bother to finish, but even before I had Monarchy, it was clear I was going to win.