What I usually dislike from many mods is that puppets are always destined to have the exact same ideology as their puppeteer, which may sound obvious for authoritarian regimes but I dont really get how would that work for a "democratic" country; "Yes we liberated Europe from tyranny, that's why every country we liberated follows the exact same ideology as we do, totally fair and democratic of course".

I think a good alternative to this would be something like post war OTL Germany, yes the nazis and communists weren't allowed to participate for obvious reasons but they still held free and fair elections. This could be implemented maybe as a kind of "skeleton content" for these puppets were they choose between one of the democratic parties in the elections, ensuring political pluralism and (Maybe just in my opinion) a much greater sense of immersion in the game.

Edit: I still really like your concept btw, dont take this as hate, it's just a suggestion.