I would wish to see castle improvement such as castle levies.
a. Castle levies are solely for defense purpose.
b. Castle levies will not able to follow marauder troop for conquest.
c. Castle levies able to upgrade using gold for more levies units or better tier units
eg upgraded level 1 castle levies offer x1 tier 1 unit at cost of 50 gold
upgraded level 2 castle levies offer x2 tier 1 units at cost of 50 gold
upgraded level 3 castle levies offer x1 tier 2 unit at cost of 100 gold
upgraded level 4 castle levies offer x2 tier 2 units at cost of 100 gold
upgraded level 5 castle levies offer x1 tier 3 unit at cost of 100 gold
upgraded level 6 castle levies offer x2 tier 3 units at cost of 200 gold
upgraded level 7 castle levies offer x1 tier 4 unit at cost of 200 gold
upgraded level 8 castle levies offer x2 tier 4 units at cost of 400 gold
d. Castle levies type are base on terrain that castle had situated.(eg. swamp castle level 1 will have orc as levy unit. swamp castle level 3 will have wolf rider as levy unit.).
e. During combat phase castle levies are always put in front of fight order, once it is destroy will regenerate in next turn
f. There is no upkeep for castle levies