Give the player the ability to assign a few ranks among the brothers. I won’t suggest the titles, as I’m too lazy to do the proper research of what would be true to the period.
Mechanics:
-You can only assign a limited amount of rank (example: max 3 Sergeants, 1 Captain, etc).
-Certain ranks cannot be assigned until the brother reaches a min level (Can only be assigned Captain at level X).
-The ranks provide morale and possibly other bonuses to that individual brother, and nearby brothers.
-As a trade off, their death or rout can have a big impact on morale.