So, the main problem is the unique design and features.
Maybe Rohan could have on outpost the Big village. This building can add the better infantry and defense for Rohan.
Village will have several interesting features(Price: 1500):
1) Tower shooting at enemy units
2) Heals nearby units
3) In this village you can to recruit peasants and farmhands on level 2.
The village can specialize to only one of three options, you must choose between:
1) Military camp(Price: 500): Around the village is several new military tent.
This feature unlocks a new spell:
Selected peasants and farmhands will get a better value and new design(Rohan swordmen and spearmen from spellbook in 3.8.1).
2) Village's stable(Price: 750): The new building for the village, the stable.
This feature unlocks a new spell:
Selected peasants, farmhands and archers will get a horses.
3) Residence of the royal guards:(Price: 1000): The village is guarded by several members of Royal Guard.
You can recruit battalions of Royal Guard on foot with sword and bow(max three battalions).
Design:
The main building is the old Rohan barracks:
And around this building is several primitive houses:
Village's stable:
What do you think?