As with almost any subject about relationships, I think it’s difficult to say what are the things that we are looking for, as it’s a purely personal perspective between those involved. If your needs are being fulfilled, and you are fulfilling those of your partner(s) it’s healthy.
I don’t think there is anything sopecifically positive in BDSM that is exclusive to it – any of the positive aspects can equally be explored by vanilla partnerships in their own way if that is what they want… so is there anything intrinsically positive about BDSM? I’d say not.
It’s positive for me and my partners, because fulfilling that kink is one of our needs. In my case it can help a lot with trust and openness, but I don’t think BDSM is a prerequisite to those positives – just a tool i prefer to use over other approaches.