You mean in the top/bottom corner? It should only show your own personal kills. I think displaying all of them, all the time is a bad idea. It encourages the kd/r mentality. Red Orchestra does it well. Sporadic, or only yours. Maybe at most, your squads.
As far as it concerns these "pro" snipers, I think jump infantry (a.k.a. Poweraxe to the face) will solve that problem, or at least make it more difficult for such players to stay in one spot.