I don't know if this is a bad idea or not but maybe you could add a culture thing so to where a nation has a culture that would give it a higher chance to align it more with other nations that have that similar culture, for instance a country with a collectivistic culture would have a higher chance to align with ones of that culture, some culture ideas could be, Individualistic cultures, collectivistic cultures and nomadic cultures. And also have it be where they can go from one culture to another given enough time