Sims helping other sims to resolve negative traits

I like the idea of a therapist career. And treating traits would be cool if we are in total control of such changes. I worry NPCs could talk my non played sims into changing their personality, and I'd dislike that. If only being able to actively played sims, fine :)

An alternative could be that traits were faded rather than replaced. I'm not sure is trait A would become more dominant if trait B was faded, though. Perhaps we would not see much of a difference unless the entire trait system was adjusted.