when I besiege a more civilized city, it usually has 4 gates that can get rammed, and you can use ladders to scale the wall as well. So you can create many points of contact and put your numerical advantage to use.
However, a primitive settlement, for example, the ones in northern Italy, some have only 2 gates, and I cannot build ladders to scale their fence... So I can only cram units to 2 choke points, and watch a long attrition battle.