Agree that the degree is likely not relevant to treatment outcomes. I've had therapists with several varieties of degrees over the years. One PhDs was meh, and one was fairly good. One psychiatrist was very good for therapy, another ok, and others terrible for both medications and therapy. Etc.

These are the traits that stand out:

- natural interpersonal skills
Some have this and some don't. Analogous to giving a speech-although speech giving is a developed skill in a sense, some people are just good at it naturally. Because they can give an effective speech does not equate to being more or less knowledgeable about the content of the speech. And those good at speech can deliver good speeches no matter what the topic. Similarly, Ts with good interpersonal skills can deliver good therapy for multiple types of clients.

- ability to apply knowledge
Self explanatory but underrated. I also think good ones will study beyond their school and self-teach from different orientations or schools of thought, and keep abreast of new research and apply it in practice.

- compassion
This is opposed to being primarily needs driven. After some time, I can tell when relating to someone who is driven more by their own needs vs driven by compassion. Everyone is driven by their own needs to an extent, but I think the ones who have balance are better. When the scale is tipped to far to the self need fulfillment, it rubs off too much and can't be hidden.

-motivations to be a therapist
A psychiatrist may have wanted to be in the field or ended up in the field because they couldn't rank high enough to get their preferred medical specialty. A social worker may choose the career or it could be someone who wanted a less demanding/less intellectually challenge degree. I don't mean to imply that those who chose the field will always be good, but I think it makes a difference.

- ability to not get entangled with client (solid sense of self)
Too many issues to get into here.

I'm probably in the minority here because I think the concept of 'the match' is overrated and gauge a therapist's abilities through these big picture issues. In my opinion, the nuts and bolts of things that drive many conversations here (eg, boundaries) are under the umbrella of these concepts, which are discussed less often.