Why can't we create puppets?

I know that we can free nations that preexist or that can be released (ie: Amazonia or Occitania), but for example, why can't I create a Rhineland puppet as France, or an Indian republic when I own a few south Indian province and that I want to do neocolonialism before it was cool, but in a roleplay manner? I feel the lack of freedom in creating puppets or entirely new nations, which happened in the timeframe of the game is lacking. It would be cool if we could do that when there's a dlc that actually fixes diplomacy.