Suggestions?
I like the changes so far and I think that are good improvements. I have three suggestions though, that I don't know if you can put in the game, but that I'd like you to take in consideration.
-Factions. I'd like the idea of different factions inside a province and more in general inside a state. For example, there can be the factions of royalist, nobles, peasants etc. Based on your decision you can gain or lose reputation with a faction, and of course there is no pleasing them all. This'll conduct in a situation in which different factions can and will fight, starting a civil war if you're not careful. We can simulate the American Revolution that way: with the faction of Americans slowly gaining power in the colonies, but at the same time with the faction of loyalist inhabitants of the colonies fighting for UK when Americans rebel, which is historically true. The regular army can have the opition of disbanding or integrating loyalists units but only if they are present in the province.
-State of agitation. If there are different factions (but even if there are not) there should a state of agitation if population of a province is hostile to you. This state of agitation should affect every aspect of the province, as trade, productivity, able men available. That'd mean that if you overstretch and you can controll a province with enough army to clam them down and you don't have good policy the overall efficiency of the state can decrease and even blow up in total civil war, a period of chaos. I think tha this system woulb more realistic that a province suddently rebelling.
-Sieges. In EU sieges have been misrepresented badly. You just need to stay in a province long enough and sooner or latter the province will fall. That is not historically true. Even if there is not an external intervention an army can't stand forever in a place. Case in point Albania: in 1444 the minuscule country rebelled against the Ottoman Empire and resited for more that 30 years against the army that conquered Constandinopoli. They did it because they had a general expert in guerrilla tacticts and some very badass castles. While Scanderbeg attacked Ottomans supplie lines, the castle of Kruja stood against every attack. In the end, Ottomans had to leave before the mountain passes were blocked from snow, because they didn't have the food to spend winter in the siege. Deseases too could very well put an end to a siege. This is totally irreproducible in EU and it was a big tactic problem during medieval times. I suggest very strongly that it should exist at least a time progression in wich friction increases progressively, especially if you don't own the provinces that connect the sieged province with your land (or if there is an enemy army on those provinces) and especially during winter.