The population cost for me is necessary to reflect the difficul to raise huge army in 1500-1600 so the majority of troops were mercenaries. Another thing is the limit of population due to bubbonic plague and lack of food. So the cavalry units have 2 population cost to reflect also the elite status (they come from patricians) and their low number, and other troops 1 population cost, and the mercenaries have no population cost. For Netherland I have raised the original number of city (3) to 4 but if necessary we can raise it to 5 or raise the number of unit at the start of the game. What do you think of this?