I think being able to equip faction colored armor to our units would be a huge improvement to unit diversity. Make it just like the clothing options where you have the base colored armor (what we have now), the primary colored armor and the secondary colored armor.

While you're at it I'd like to see upgrades to weaker armor as the new armor tiers are unlocked, purely cosmetic alternatives to the same armor. Like when we unlock chain add "reinforced leather" or whatever that has the same armor rating and material costs as chain but uses the leather models. So we could for example keep our archers looking like archers while keeping their armor up to date, rather than "heavy knights with a bow."

I really feel like generic units are boring, and simple cosmetic stuff like this would seriously help a bit.