The only other Clancy FPS I've played was TC Vegas. Besides the Co-0p mode which was fun...and I sort of miss, it also had the ability to hit L1 and hide behind a wall/barrier...etc. From there you could take aim and have the character move out just enough to fire while protected on the lower half, or even blind fire.
Other useful tools for the character were night vision and IR through headgear...not just through a scope like BO.
I'd still play it once in a while if I thought anyone was still one there...it's just such an old game now...