Muh Dude this is kinda a slippery slope, penalizing bottom feeding and incentivizing hitting up i tend to think more or less army efficiency. If you make this too punishing people wont attack and just farm.
Bottomfeeding will always be tehre cause its the best way to grow. The only counter to it are alliances, if your a solo player you will get killed most likely. I dont know if i mind this as it forces players to play with their provs etc. This becomes a problem when there is a runaway prov/player who just keeps everyone else down. That is when we gang up 1 person at a time and keep them broken out of the helping hand of their prov/allies.
Personally i cant think of a way to stop people from hitting those smaller than them. It is the same in the real world, the weak are conquered by the strong whether it be economically or militarily.
