Had a thought about the new primitive tier: could this be used to represent natives in at least some of the "empty" areas?
It rather annoyed me that American Indians and most African provinces will just sit quietly and allow themselves to be colonized. IRL conquering these areas took both force and diplomacy. Representing them as full fledged nations in Victoria II wasn't a better solution though.
Maybe having them in game as primitive could work, especially if you had different rules for primitive-v-civilized diplomacy and warfare. This could allow for more realistic westward expansion in the US and colonization in Africa. A player should have to weigh the pros and cons of giving up some of their land or autonomy to a big hungry power (like US or UK) in order to buy time for reforms.