As far as whether Milan is a strong faction in the game, it is IMO, I think mainly because of what deathfire mentioned, their good units are militia units and cheap to maintain, whereas most people surrounding them (except probably Venice) have to build castle troops. This is why I think France always gets wiped out, their good units are expensive to build and probably can't build too much either since they're elite units (and basically 4 countries attack them). Those two cities they have are also rich, and with two cities your yearly expenditures will be very low.