Empires : Dawn of the Modern World had such systheme, it worked well, the only weakpoint was isolated animals( a small groups of bears in a closed narrow space ), they would start to multiply until all the empty space is taken... An interesting video(at least the 2 first minutes), "In which I discuss the pros and cons of olive farming in the ancient world, and then get kicked for my efforts" :
(the author also did points on longbows, shieldwalls, etc...)