This is a great post, and with the ambiguous conclusions > as everything in psychology :D

I have tried a few forms of psychotherapy as a psychology student, but each one of them for short, so I am not sure if I can really compare. Here are my experiences:

• exchanging emails (Constructivism): It was great that I could come back to the written text whenever I wanted and think about it again. However, I think that the disadvantage comes from my side - that I was surely not writing as spontaneously and in a raw manner as I would speak face to face.
• video-calling (Gestalt): The therapist was a bit complaining that we cannot really see each other's gestures (as you also mentioned). For me this was fine, and, of course, a big time-saver.
• face-to-face (Psychoanalysis): I remember that amazing feeling being in that place decorated totally in psychoanalytical style, and so comfortable. I felt more that I am setting time for the sessions, and that I am really committing.

So, regarding my own feeling, I think that psychotherapy face-to-face feels more intense, while video-calling feels more like 'one of the calls I do during the day'. About email counselling - I think it is fine only for short issues, some current problems, but I don't think it can really be effective and efficient. :)