It seems that in every match I've played, all snipers are one hit kills regardless if they land a headshot or not. I remember I was chasing after a sniper in the subway tunnels with a shotgun. I must have shot him in the back three times before he turned around and shot me in the face with an SV98 (from maybe 10 meters away). Several other occurances were happening where it almost seemed like some people had aimbot because they would run around the corner and kill you before you even had a chance to pull the trigger.
Also, due to the fact that this game does not of anti-aliasing (smoothing the jagged lines), snipers have a huge advantage while prone or while indoors (like in the buildings in the last part of OP Metro). The scope reflect seems to only happen 1/4 of the time as well. I think that something needs to be done so that they aren't so hidden. I mean, their guns kill in 3 bullts or less, little to no recoil, and then the fact that you can't even see anything because of all the jaggies past 100 feet? This is going to be a huge issue.