Having looked at your files, I think this is a great idea. Even more extreme changes to cost/maintenance are possibly merited. However, I was thinking about a more broadly compatible way of doing this, such that it could cover all cultural units introduced by various mods / collections. Could a cost be added to the budget (call it MAA-balancing) which adds enough maintenance costs to make up for the fact the up front costs and the regiment sizes aren't easy to mod? I.e. put all the balance change as an overall added cost based on a ruler's total number of heavy units? I think this would not improve AI decision making but as I believe AI considers it's monthly balance when buying MAA would still push it to lower cost/maintenance units even if it couldn't consider the 'real' maintenance of heavy units at the point of sale?