War weariness has already been mentioned so that is back in. Casus Belli will at least help make defensive pacts more palatable. I am pretty darn sure they will be justified significantly reducing the warmonger hit from them and making them useful. Pledges could be useful. If the modding tools are for real this could be an amazing system. If they also weight warmonger depending on relation and agenda this system could surpass the civ 4 system. It seems that agenda is in. Roosevelt is said to not mind wars on other continents but be super sensitive to local aggression. I find the civ 5 system to be not nearly the step down many people say. 4 was dominated by religion and then just trading with your partners. If warmonger is decreased for civs who denounced or are at war with the civ you attack that would really help the system. Increase warmonger with those civs that have declarations of friendship. With the civ 5 liberation trade and bribe system that would be a the best diplomacy ever. Especially since we can't use relations to pillage the Ai for tech.