How can the AI be made a more selfish ally?

[Moah]

I guaranteed the independence of byzantium once as poland, the following war set the ottomans back 50 years. I imagine the ai tries to do the same when allying minors under threat from their rivals.

France did something like that to me. I was playing Brittany, Provence DOWed me, France swooped in as an ally (that i didn't want, I suppose they had guaranteed me or warned Provence), and flash-sieged all of Provence before I could even get a troop in Maine (where I had a claim).

Then they got pissed of at me for not giving them anything.

 

[Moah]

You wanted a french core as Brittany? I also like to live dangerously.

I just wanted to expand somehow... wasn't able to, in the end. France ended up attacking provence later and taking their cores anyway. I ran like a cowa... smart man, and colonized as much as I could.

Would you have been able to win alone? If no, they're totally right. And besides, it's their cores, thus they are entirely right in being pissed at you for not giving them back to them.

I didn't say they were wrong, or that the game was broken, just mentioned one time when this happened. I probably would have been able to get it (though with much more difficulty), I had other allies (that I had actually chosen).

In the same vein as this thread, another thing i'd like to see is for war participants to be able to influence the war leader into making peace.
I've gone to war with allies who are being trounced but won't accept peace while my provinces are blockacked on all sides, and I can't do anything.
Separate peacing would cost me too much and the result is guaranteed anyway.