I don't know why people are soooo obsessed with snipers. If you're stupid enough to run in open areas or try to fight someone with a scoped weapon from distance, you really deserve a headshot.
Locate the guy (most of them stay pretty much in the same place), go there and shoot him. The scope makes him completely blind in at least 340 degrees around him. At close quarter his weapon is useless (unless he is that much better than you). And to make things better, if you avoid open areas, the guy is useless and it's like one less player on the other team.
Just to clarify, I'm not a CoD fan and it's pretty rare to see me sniping (except by Resistance 2 with the Marksman and Killzone: SF. But even then, I use medium ranged sniper weapons that still have some close quarter capacity and are mainly to snipe in the ground behind the line formed by your team).