I have to say, I am having so much more fun with warfare than in any other paradox title.
I was a huge fan of Europa Universalis: Rome, mostly because of the combat, and it's why I love Imperator as well. Maybe I'm a masochist, but I like the work needed to get the right resources you need for the units you want and just how much army composition affects attrition and how those two mechanics come together to create a new experience.
With the right armies, you can definitely punch above your weight class and it feels great when you win wars in your neighbourhood and all your neighbours can do is sit and grumble.