It's a bit anoying to, let's say, have two French countries, that both have different nationalities. It doesent make sense that France 1 has to asimilate land from France 2. Isn't there any way to make a system like in Victoria 1/2, where every country has accepted cultures. Maybe we could have the ability to make our own cultures, and if we make new countries, we could have the option to asign them accepted cultures. The cores can stay the same, but when we make new scenarios, we could add to each province as many cultures as we think are necesary. Maybe when raising soilders, you could have the option from wich culture these soldiers should be.
That's my suggestion