It could be in terms of ability usage, or in terms of aim, but I'd be interesting to hear any thoughts! My instincts say that aproto, crashies, and nitr0 are definitely up there.
aproto definitely, this man is insane as a sentinel, his aim is far too good, in a match easily he can get 50% HS rate with a huge ACS as a support player and a good ADR.
Well I guess aproto plays raze on a couple of the maps, but he still counts as a support player in my eyes. However, I'd say Shot Up (plays breach occasionally) doesn't fit that bill.