I'm curious as to what the system for picking up weapons off the ground is going to be. In insurgency, picking up weapons was entirely useless since you only received one magazine for the weapon. I would hope this changes in sandstorm. It was really irritating when I would go on a 20 player killstreak just to run out of ammo. Sometimes I would get lucky and find an lmg on the ground.
I would suggest a system that allows you to search dead users for their magazines or ammo for a few seconds. Their magazine count is added to yours so you can use their weapon.
Spitballing from this point on, possibly add magazine sharing too. It would be great to share an extra mag with a teammate if they run out and happen to use the same ammo type. I think this would incorporate nicely with the new ammo system they showed off for sandstorm already.