You're one of the people i see using an xbox 360 controler thinking you can compete with mouse and keyboard users, if you are then have you realised your controller is just not good enough.
I say this because i see alot of over compensating, very slow aiming motion and the complete inability to track a moving target.
Has it ever crossed your mind that it might be the lag that causes it? I mean to you it might look like those people can't aim, but on their screens they might shoot you straight in the head and just not get hit markers and kills for it cause your caracter is actually a meter to the right or left to what they actually see on their screens. Read forums dude. Everybody's talking about it. Happens to me as well with my 100Mb down and 45Mb up. Unbelievable? Yeah, that's what i thought as well but then i bought BO2 and it proved me wrong
Have you ever thought about getting a xbox? I mean, im a ex wii player but im not gonna use a wii mote in the pc version. The pc version is made for the mouse and keyboard.