I like the idea of units being trained organically with a weapon via use, maybe track 3 weapons per mercenary; current, best, 2nd best. For me a more organic training system over the level-up system would be awesome, not sure how that would play though.
I would prefer an upgradable wagon that unlocks merc and inventory slots. But I honestly don’t think this game suits allowing players to collect more than your troops can carry. Imagine how much it would cost you to keep troops on standby, or have supplies sent to a warcamp. I understand the desire to accumulate loot and upgrades to track progress, but with procedurally generated loot it just seems like you’re never going to have enough space.