A random thought I’ve been mulling over. Should players be able to upgrade units at all? I feel like upgrading units, combined with there being no real limit to how many units you can have, cause just a tonne of balance problems. Indeed, it seems really odd to me that there is no limit on how many units you can have. The way the game is now you’re sort of incentivised to keep building units (at least in the early game). Early units give you a lot of bang for your buck, and even more so once you factor in experience and upgrades. If I’m not warmongering, I still tend to build quite a few ancient era units and then they just sit around and then get suddenly upgraded when I get attacked or someone attacks me (hey presto). Looking it another way, there never seems to be a reason to disband units. It make sense to keep ancient era units around forever, because they provide low cost fog busting and or garrison unit bonuses, and always be instantly upgraded if suddenly war. I think the game would be more interesting if upgrading was harder. Perhaps you could have some sort of “force limit” giving a soft cap to how many units you can have. It would increase maybe with governments , policies and or military infrastructure. Going over your force limit would massively increase maintenance and production costs for units and maybe also create amenity issues. The big catch would be that more advanced units would eat up more of your force limit, so upgrading all your old units wouldn’t be an option any more - indeed, you’d have to disband some units to make room for upgrading others. Having more restricted numbers of units - and making overall harder to keep rolling over your army into more and more advanced units - would not just make the AI more competitive but would maybe make loyalty and city flipping a much bigger deal. Because you couldn’t just override loyalty by steamrolling a tonne of cities all at once, and your own cities flipping which create much bigger drains on your (limited) military.