One: doing one own's mini events is nothing opposed to have DMs doing it. Autonomous playing is of course a main part of everyone's gaming. I'm not suggesting here there are babies needing nannies. Abilities of normal player to interact with the setting and the surrounding world are nevertheless limited. Example: if I decide to play the waitress and enter to, let's say randomly. in the Tigan's and start working there, autonomously, taking people there I might be accused to ignore NPCs, to ignore what that inn is, what its setting goal is. Plus, the surprise element provided by a DM is something characters can be able or not to produce.
Second: I still don't see how the topic "monsters" enters here. Ravenloft setting is not just monsters. Otherwise we might have more dungeons and set all the RP in there. A new rule system about MPCs can be good. Might assure some persistancy in the horror mood. But again, in this topic I was trying to speak of something else. And many others have understood.