1.3.1 was pretty good in terms of war frequency. Even with no material content outside fighting, moments of peace to consolidate are good. I'm not playing 1.4.1 until the bloodthirstiness is wound back a notch.
In the long term, there needs to be some kind of justifications and specific objectives for wars. We don't need a casus belli system as restrictive as CK2 when half the game was finding an excuse to actually go to war - but without structure, the snowballing that people constantly complain about is the only natural ultimate outcome of wars.
AI lords aren't voting for peace because they want more stuff, and they need wars to get stuff. They have no sense of self preservation, it's get stuff or die! Other motivations and/or restrictions are needed to create interesting dynamics of play.