I wish so much that people would talk more civilly on these threads. Let's not have the mods come in.
That aside,
@WeissRaben is making a good argument and one which turns up frequently, though I think a lack of historical knowledge tends to make it come through badly. Huge empires in the timescale did not, by and large, collapse castastrophically due to rebels (which isn't to say that rebels weren't a problem - and there were some very successful ones, such as the Dutch). The Catalans rebelled over and over again, and never achieved independence, and after the Ming-Quing transition the borders of China were much as they were before. But there are struggles which were of tremendous importance in history which are not represented: for example, almost all states in the game's timespan had difficulty collecting a stable revenue for periods of time, and this contributed in a big way to the downfall of enormous empires - the Ming and the Spanish Empire being the most obvious. If you couldn't raise revenue, you risked your army turning on you, and your enemies coming for your blood. In EUIV your economy just grows and grows steadily as you expand. I'm not sure how you'd implement interesting tax reform mechanics, but we have interesting army professionalisation mechanics, so I'm guessing there's a way to do it. That's the kind of feature I'd like to see.
Also, for the record, I agree with
@bbqftw that a lot of complainers-about-blobbing seem to spend a lot of time denigrating a skillset that's completely legitimate and has it's own deep interest. I'm very much against a 'git gud' mentality where it conflicts with 'enjoy the game in whatever way you like', but that has to go both ways.