Thank's for all the info but this is beyond my skill level (which is pretty much limited to changing numbers)
If anyone is interested in making such a mod: what I was trying to do was stop minor civs from building "offensive" weapons. Specificly: siege units (catapult tree), light cav, and the naval siege (battleships ect). The other way would be to make them prioritize melee, anti-cav (spear line), ranged (slinger line), and maybe the privateer line (because it's somewhat hidden and could surprise an attacker).
If someone would like to try making a mod like this I'd be happy to help test it.