Now this is another pipe dream of mine lol but I figured id toss it out there anyways.
In naruto the countries are almost always in competition with one another for some reason or another.
I propose that each area in the game is worth a certain amount of ryo each and this ryo is awarded to the village that has captured that territory. Leaf, mist, cloud, rock, sand and so on Can not be captured and would each give the exact same amount of base ryo lets say 100 ryo per day.
The ryo collected from owning a territory could be spent by the kage in order to improve the village defense and perks. The kage could buy Traps, Guards, elite guards, and so on To help defend the territory that they control. these guards and traps would defend against invading villages trying to take over the area. If successful the invader defeats all defenses they then gain control over that area. The ryo collected from these areas can also be spent on village perks. Better weapon/armor shops...possible bonus exp or other things similar to this.