I find it very infuriating that I can not do any diplomacy with AI countries! They take up a decent portion of the game and being able to maybe create an alliance with them or asking for peace would be amazing. I find it stupid that AI countries get mad at me for declaring war on other countries in this game even though that's the whole purpose. Not only is it annoying when they get mad and put a trade embargo on me but also annoying when a majority of them decide to declare war on me making it impossible for me to win the game as I am swamped with AI. If you look at total war games you can see how they implemented the peace feature in their game. The AI was able to accept your diplomacy offerings and even counter them asking for money. My final suggestion would be to take away the moral penalty for declaring war on a country that has already declared war on you.