Back to back killcams today showed a guy getting shot several times only to ADS and kill his target instantly with a quickscope. Had he been using any other gun he would have died without landing a shot. This is one of the biggest reasons people hate the quickscoping, it completely negates shooting someone with anything other than a OHK weapon if the person you're shooting can quickscope you with a sniper kill you instantly. At least shotguns have range, snipers don't.
My solution is quite simple and it should be put into effect on all weapons. When being shot at ADS time should be increased by at least 50% and movement speed reduced by 25% (Toughness does not counter this only flinch). No more shooting someone only to get turned on and pull off some lucky ass headshot that you got because flinching moved your crosshair up to the persons head. No more emptying a clip into a kid and getting OHK by a sniper.
This doesn't remove quickscoping from the game and if the person had terrible aim you can still win the gun fight. All this does is reduce the amount of BS associated with shooting first and bloodying your targets screen only to die from a few lucky shots
QSing should not be in a the game. I lump it in the same category as hacking. Your using the games inability to compensate for the movement so it just makes the assumption the you wanted to aim at that specific location. ADS time should be slowed 70 percent, it should be a weapon for hard scoping. You know a exploit is overused when you are in a lobby and there are 5 QSers in the lobby running around as if it an AR. TreyArc doesn't want to take it out due to the little kids who run around doing trick shots with it.
Who doesn't love to turn on a guy? If I get turned on, it's my fault. As for getting turned on by a quickscoper, I'll tell him, "nice kill" in the brief time he can hear me after he kills me. It usually is a really nice kill.
If you can't kill a guy fast enough before had can turn, center, then ADS, that's your fault. Not the games.