I have not completed one single COD campaign or played it for that matter. I hate what they have done with campaigns over the years. I honestly believe that the COD series killed the throwback style campaigns that we were used to playing that actually had replay value on the regular xbox and playstation systems.
The old throwback, vintage campaigns in older games were just more fun to play. You actually had so many ways to finish or play through a campaign instead of the very "linear" way to play them now.