We will not create such a forum. There are more than enough places to go online and rant or complain about things you don't like or feel like you were harmed by. We even have a social group forum for such things:
http://forums.psychcentral.com/clients-betrayed-t/
And you're welcomed to create your own social group if you feel that one doesn't meet your needs.
Inevitably, people are going to talk about their therapist in the psychotherapy forum -- you can't separate the two out, since one of the "active" factors in the success of psychotherapy is the therapeutic relationship with your therapist.
While sometimes it may seem like the forum has too much complaining or such about one's therapist, it comes and goes. The forum is a diverse gathering of people sharing their psychotherapy experiences. I wouldn't want it any other way.
DocJohn