Pay particular close attention to 19 minute mark.
It really defines how to setup AI to have a good middle game.
I will save this video and replay 19 minute mark over and over till it sinks in for me....
There is a form an alliance with other AI if player is close.
I copied down AI's methods and strategies listed below:
To get a better Middle game:
It is recommended to get average of other players in game: Cities, Number of units, type of units. This way the AI can try and cope with your builds.
So you could make a sliding bar or button menu to increase\decrease skill level of EDCE AI.
A General that is cautious, so he builds up first and has a rudimentary defensive guard unit watching over clump of cities while a hunt\attack group is formed later to seek out targets of opportunity. Or an overly aggressive Ai that risks it all. Or something in between.
You could assign skill level based on the name of the random general name. Just place General names into appropriate array of Cautious, Aggressive, etc...
Units are given a fear algorythym based on damage, units in their group that have been killed and type of unit doing the killing.