I've noticed the game plays a lot slower since the new DLC was released. It's just a general performance degradation as more features have been added to the game
So basically you are saying adding 900 new provinces and 100 new countries was OK for performance in 1.8, adding 365757382 things before El Dorado was OK, and then suddenly release of El Dorado - with a bunch of events and new buttons (don't get me wrong it's awesome dlc) suddenly caused ''general performance degradation''?