I am going to throw Melhed and Ar Agyr into the hat. Simply because we are both always trying to do something. Albeit our nobles are not as talkative, but still responsive when they need to. So join us if you want an immediate war because we are almost always in a war.
Thalmarkin has responsive talkative and bullish nobles but as of now, it seems that they are feared most so everyone tried to be nice with them.
Riombara i am not quite sure about their nobles, but it seems that they are growing too big to support their nobles.
Nothoi it seems have quite responsive nobles too and was at war with Riombara. No idea why they stopped, really.
Caelum, Spearhold and OG. I will let them tell you themselves. Haha