Ok, thanks.
I just seem to come up with new questions, so here's more: in zone12's excellent video LP I once saw Holy Roman Empire become Germany on the political map mode. Later it was HRE again (and full of revolts). What happened? I reasoned along these lines: royal authority was increased or power otherwise centralized to the crown, which turned HRE into a more coherent entity (Germany) and later the emperor was forced to back away (and Germany became HRE). But what really happened?
Also, is it as easy to mod in creatable kingdoms as it's to mod in new countries in EU? That would solve the Dutch kingdom issue.