1) Dedicated Servers
2) Bullets more realistic
3) Shoot someone in the legs a couple of times they go into a crawl animation
4) Noobtoobs have less radius
5) Night Vision Goggles + Thermal wear to help see enemy, (Not weapon attachment).
6) Takes longer to regenerate health.
I mean common, 15 seconds to recoup from 50 bullets entering your torso.
7) Proper re-load times

Proper primary to secondary switching
9) Armour selection, Light, Medium, Heavy, Lighter it is, the swifter you are, however less bullets it takes to kill you, heavier you are, the slower you are, but you take more rounds to the chest.
10) A Game without hackers