I think that if a MLCer recovers at a certain point and attempts to reach out in a meaningful and responsible way, it is always possible to become less dim or dark and take a wait-and-see approach using a lot of caution.
Until then, I think that very low contact is important, both for the LBS protection and also not to make a volatile situation worse.
Many highly volatile, abusive, "monster" MLCers have behaviors that resemble mental illness, severe personality disorder like NPD, and addiction -- and in fact this may be what is going on. There are many great resources online for these and none involve "paving the way." Most identify the importance of responding and not reacting and of firm boundaries. I feel the "grey rock" or "medium chill" technique is a very useful tool for someone dealing with manipulation and abuse.
I also think Larry Bilotta has an idea along these lines, be nice and pleasant but no time for MLCer. Can't talk, can't visit, can't stay. Act as though you have just found out that your MLCer has been institutionalized.
I feel that telling a newbie to detach or do the 180 is like telling someone whose home was just bombed out that they need to detach from the home, or act cheerful and busy so the home can be rebuilt. Few in that level of emotional devastation can manage this. In this case, low/no contact is a very helpful realistic guideline that protects a vulnerable LBS from an irrational and aggressive MLCer.
One fantastic resource online that OffRoad recommended is Out of the Fog. It has really great, detailed guidelines for dealing with people with suspected or diagnosed personality disorder/mental illness.
I am someone who spent several months engaging with MLCer not understanding what was going on. Then I attempted a more detached style of interaction. While this was valuable from an observation standpoint, he ended up cycling back into aggressive/monster state and continues to cycle from attempts at being "friendly" to being angry and controlling even with almost no input from me. All to say, no contact may reveal just how little we have to do with any of this.
I also feel in terms of LBS personal growth no contact is invaluable. It has helped me have time to reflect, learn from this experience, and above all I feel really learn that I am responsible for my own responses to things, and that ultimately what is going to make me feel good or bad are my own actions and behavior. As Watcher writes, this distance is a time to really look back and look forward.