Nations can now be given a value to increase mage recruitment. Some nations (like mictlan) have almost only mages, while others are the opposite. We can now lessen the chance of a given AI nation recruiting nonmages. It might appear in modding as well.
Similar for resource light troops, but this took more efforts and thought from me, so it is only in its early stages, and might not be used.
VedalkenBear, I noticed the same thing about the BI mod, so I've started using either the gold only or gold & resources version because that takes care of it. Just means that you never ever use enslave mind or charm against indies unless you want to go bankrupt.