The Mercenary 说:
We're planning on fleshing out diplomacy more.
Yihaa!
I am one of those idiots that like diplomacy and strategy too!

Oh! and tactical choices as well
I mean, the guy is kinda right. Allies don't declare war on each others for no reason or out of the blue. Now, it doesn't mean the AI has to be stupid. For example, if they see a big disparity between your strength and theirs, they might be tempted to declare war, no matter how good your rep is... Tough world! But you should kinda see it coming by them "picking" on you (asking you for bribe money, ransoming your caravans...) and, if time and distance were a bit more realistic, a 'signal' could have been some of their lords tresspassing on your territories...
Alll of that would be accompanied by potential loss of relationship, unless you meakly give in - trying to buy yourself time.
Forming strong defensive/offensive alliance would be great! ... i.e. something deliberate rather than just happening to be at peace with a given a kingdom that is also at war with one of your enemy...