For the sake of everyone that has ever needed to put an army together:
Automated army loadout.
Based on the number of troops you have on you in the fief you are sitting in, the system automatically picks from your gear (selectable) and the fief gear an appropriate standard selection of equipment.
The logic could look like this: per each 100 troops, select e.g. 100 armors (x light, x medium, x heavy) + 100 helmets (...) + 10 horses + 5 siege shields etc. and transfer them on you. If any category has less items available, select only what is there (and highlight what's missing).
Ideally you could select different army types for the config, such as e.g. "Siege", "Infantry Heavy", "Cavalry Heavy" and customize after the auto loadout to your liking.
Probably a ton of work to implement, but it would reduce the micromanaging a lot, especially late game.