I like the idea of this mod, but lets say you have a huge empire and united it under a single culture group. For example, lets say you have a gigantic norse empire that has expanded to the entirety of the british isles, france, italy, spain and germany, and after centuries of rule, all of them are 100% norse. This seems quite unrealistic. I propose that when you convert any culture, and then break it down, it merges the host culture with the conquered culture. For example Norse-franks, or Norse-Lombards, and so on. You could do the exact same thing for every single vulture in the game, as if every one of them was a host culture. The only time cultures shouldn't merge is if a culture takes back land that belongs to it's de-jure culture zone. For example, lets say a peice of scotland becomes anglo-saxon, and then the pictish take it back and convert it back to pictish. It should remain pictist, it should not become "picto-saxons"