I was trying to create a new faction for my own entertainment, and an idea came to my mind.  In my custom faction, I was duplicating the food generating tech in the Adventure tree, so that when I researched it, three food tiles would spawn and the tech was repeatable.  It was entertaining to slowly fill the terrain around me with food tiles. 

But my thought was, how about creating a custom faction specifically for the AI to use that had techs like these?  Techs that gave them a unique advantage, but not technically a "cheating" advantage (although it could be argued).  It doesn't have to be as crazy as a three food spawning tech like mine, but it can be as simple as recreating their tech tree to have a unique tech tree that may be more beneficial to them.  Factions are planned to have their own tech tree anyway, right?

I realize that people probably want to play against an AI that plays by the rules, ie, the same rules as the player and play well instead of a "cheating" one, but I hope this suggestion might be a little helpful to those who want a different challenge.