I really think that Blizzard should classify Medivh as a support at least as far as the QM matchmaker is concerned. They don't have to actually change his classification, just how the matchmaker treats him.
I am not saying Medivh is broken. I am not saying Medivh is OP. I'm saying that the fact he's classified as a specialist makes for some incredibly lopsided QM games. Pugs cannot deal with a Medivh on the enemy team, particularly when QM has so, so many no-support games. One team having a Medivh is just as unbalanced as one team having a support, a situation Blizzard specifically engineered against in the QM matchmaker. I'm saying apply that same logic to Medivh since he functions as a very effective support if played by people with a brain.