I'm working out the details, and have decided it would be better (though) more ambitious, *not* to put a strict size limit on AI factions.
This allows all faction types to be produced (even pure magic, but those will grow very slowly.) instead of just 1,1,3 and 2,2,1.
Prioritizing the taxes is easy enough, just a quick check on which hexes produce most.
Trade is another matter. I think, a minimum of 2 hexes for wood iron and horses should be tried for, and a min 1 on stone and herbs. After that, I'm thinking a 'Production Total' for each hex, weighted like so:
Food : 1
skill 1 items : 2
skill 3 items : 4
skill 5 items : 8
Then producing all cities that buy + required items + highest 'production total'