Hi just_ine
Seems to me that any therapist SHOULD understand the unbalanced nature of therapy itself. transference (falling in love with the therapist) is a real thing. I don't know but I think to avoid such problems the therapist is supposed to only reveal so much of themselves.
It *may* be possible for a therapist to help a person in an area that the therapist knows little about. I'm assuming that the goal of therapy is to help the person come to terms with what is troubling them. Maybe there are techniques and questions the therapist can use without fully understanding the problem area. In some types of therapy I think the therapist is supposed to be like a blank slate.
I wish I knew more and could provide more insight.