I like this idea a lot! I've been disappointed with ghosts since Sims3. They're just not disturbing enough. I think one of the interactions for a live Sim would be to get the chills and start rubbing their arms whenever a ghost (seen or unseen) enters the area the live Sim is. I like the notion of having to deal with 'unfinished business'. I like that this could be linked to a ghost trait. So far, this has been rather well thought-out. I do hope the devs pay close attention to it. If we could have something other than comedic ghosts in the game, I'm all for it.