I think the countries take too many provinces away after winning.

[Chihong Ahn 21]

Yeah, the current system allows nations to annex too many territories at once.

This is quite a problem for me because in my 1836 scenario I am working on, I saw Prussia annexing like almost 1/3 of Austria or Russia annexing the entire Turkish Balkans. 

And I think there is a little penalty to it.

Some kind of casus belli, giving more limit to territorial annexation, etc are needed.

 

[goktug14 274]

A thing like infamy or badboy can solve this problem. Like, taking 1 province is 1 infamy and it can reduce relations with neighbours. Also, infamy can effect being ally with someone negative.