I like the MW2 system of knifing, the only thing I will agree is that it needs to be a separate weapon, like the tactical knife is, or have toss in a negative effect after you use the knife. For example if you're wielding a two handed gun you knife someone, you need to take a second or two to put the gun back in your hands and reaim it. No knifing one guy and blowing the guy behind him to ashes with your assault rifle. Other than that I'm fine with the instant kill system. Let's be honest here a system like CS while its great that its a nice humiliation/skill fest or whatever you want to call it. People rarely use the damn thing seriously because it just can't beat out any of the weapons, even in close range. From years of playing I've seen so many people run in, get maybe a single strong attack and just get popped in the head because the other player has tons of time to turn, aim, and shoot. Instant kill, imo, works because it actually adds to the arsenal of weapons you can choose instead of it being a side thought that people just screw around with.