Are we sure we're going in the correct direction, as far as balancing mages? I don't believe money is a huge issue right now, as it's ridiculously easy to get capital in this mod. I think, rather, that we should focus on making it take a LOT longer for spellcasting troops to level up to their next tiers. I think we should have the experience requirements doubled or tripled, to make it more difficult to get stronger mages and to make them all the more valuable to find and retain. This should, in my opinion, fix a lot of the balancing issues simply by making mages far less common.
Also, if there's some way to make the Ridas villages give far fewer mages when recruiting, like say a max of 2 when at relation 0, that would help as well. We should *not* be able to get a full army of high-level spellcasters without an insane amount of work. Mages in DnD are just not that common, because it takes years and years of study and practice and even then, many will kill themselves while attempting spells.