There should be a system where players can stage their own revolts, similar to a claimant, but get to customize their own troops (For example, WFAS's mercenary outfit system if possible) to be unique towards the enemy's troops during the revolution.
I think it would fit the time period and game well for not only gameplay purposes but RP purposes. For example: If a player launched a revolution against the Sarranid Islamic Confederation for "modernization", their troops could be outfitted with traditional bows and arrows, as well as swords and shields for any units they choose.
I'm not quite sure if crossing WFAS Module System code with Warband's ModSys will work, though. It's worth a shot if you're willing to try it. Thank you for reading this!