Yes you are mostly right (those maps are not really that accuratem, there are supposed to be over 100 million people in NA before contact with europeans.) so balacing population and land area, deserts, mountains, and stuff like that should give you roughly equal amounts of provinces. This is the thing, if you want to march your army through a mountain or desert it was hell, and it was mostly never done, so with few provinces in the game it becomes very easy to cross this barriers. Different philosophies for different issues. Because of how the game works, crossing 10 desert provinces is not the same as crosing 2, even if they are big provinces it just doesn't represent the difficulties that nations in that area had to deal with. I'm not for deterministic games, but geography plays a role in shaping the borders of empires, and i think it can be implemented to a larger degree with existing mechanics.
