realm benefits should symbolize the theoretical trade and knowledge transfer between village imo. It can be abstracted into percentage for knowing how to grow better crops. In game physically I think it should be represented as a road. That way you would have to externally defend outside of your palisades in order to maintain realm benefit. Instead of just showing up and getting percentages automatically, you have to be recognized by at least some element of the realm community. A neighbor nearby would have to agree to connect to a road to that claim.
If a claim is connected to a realm via a road and has a superior crop, would it not make sense to confer that bonus to the realm?