@redrum I checked Civil War
Unrelated, I found a possible bug: I can't move troops in and out of Upperville (under "Manassas" rail line), Eastern Campaigns Scenario.
On topic. In my (limited) tests, it seems that resource overstacking is even worse in CW. Depending on what you purchase or not (and how much you move), some or even most resources can potentially skyrocket fast, providing practicly inexhaustible stockpiles. Supplies/Fuel is very similarly implemented to mine, troop cap (manpower) better I think.
It also gave me some ideas. Feedback very welcome.
Maybe I should remove supplies, and use PUs in it's place (upkeep & fuel), in addition to it's previous applications. Since it's needed for other things, it won't just grow in most cases, just so a few odd ones are covered. Real supply harassment is not possible anyway (unless I replace the system with a supply train unit, needed to move troops, but I bet that would mess the AI). So I guess my Supplies resource is just flavor hintering gameplay. I'm fine with wealth representing supply potential and making agricultural regions richer to balance the map.
Then I could also steal CW's manpower system (each unit has 1 manpower upkeep), just a limit on how many (non-mercenary) units are possible, and have units also cost PUs instead of manpower. Example:
Phalanx
100 PUs 80 Iron
Produces Resources each Turn: -1xPUs -1xManpower -1xIron
Fuel Cost per Movement: 1xPUs
Merc_Phalanx
360 PUs
Produces Resources each Turn: -3xPUs
Fuel Cost per Movement: 1xPUs
This also adresses the issue mentioned by @Cernel (killing off your mercenaries first cause they had huge PU upkeep, now they are just much more expensive to recruit - numbers are just examples, will need tests)
Finally, in a possible extreme makeover, I'm thinking to add Population Classes. Probably just 2 of them, Nobles and Freemen, needed for different types of units instead of generic manpower. Slaves would just be represented by the Slave_Estates Government/Structure. No Citizens, so it's generic enough to fit tribal states, unless:
UI concerns.
The way the game is setup now, I can have up to 4 resource types per territory (with a total of 8), else there are display issues in the lower bar. This could be offset by moving some resources to pre-placed structures, which is not ideal (visual burden, more work) but has other upsides (flavor, "pillaging"/destruction of productivity, possible upgrades, though the AI would need triggers to get them). Without such changes, I can only potentially add 2 resources. That's if I remove supplies and replace territory manpower with Freemen, I could add Noble (and extra Freemen) generation to some government types.
There's the resources tab issue as well though. Already with 8 resources it needs to be dragged to show gains/losses once a few numbers go over 99. Adding more resources would make this worse, perhaps even hidding current numbers. So maybe I should sacrifice manpower diversity and supplies to somewhat improve the resources tab display, cutting it down to 7 resources?