I think his Q sould be allowed to do that, because it would really suck if you cast it in a team fight and then it gets canceled due to a little edge in the way of the ability.

In my opinion you didnt make it overpowered, because his displacement isnt point and click and so, gets countered by mobile heroes.Maybe his W is a bit strong though, because he can simply run into the enemy team,W out of it and even set up a kill, so maybe the range should get decreased, if he takes an enemy hero with him.That would allow some counterplay to the ability, but I think it should be your decision. The fact that many supports isnt something new to me, i just wantes to say that...

Good concept so far but I would like to know if he's supposed to be any special role and if yes, which.

I really like this concept, because it's something specialness HotS doesn't have a displacement based support yet