Just started playing, and it's great. Just a couple of suggestions:
-Classes. I know this has been said a lot, but yeah, it would be great.
-Rocket launchers! It would be pretty easy, too. Basically, just use a projectile like a bullet, but impact would be a grenade.
http://www.liveleak.com/view?i=956_1265748979
http://www.liveleak.com/view?i=5a5_1339776675
Don't make it slow, either. As you can see in that second video, it took about 2 seconds to go about 3/4s of a mile.
-M16/AEK-971 w/ grenade launcher. You could literally just use the hand grenade, just launch it.
-Mortars? again, just launch some grenades.
-Medkits, would allow for pretty nice teamwork.
Other than those, awesome game!