First of all, the weapons that I,m suggesting are only opinions.
Shock cannon: This weapon is only to stun multiple enemies in a group for three seconds. It holds three sound blasts and takes 2 seconds to change to any other weapon.This ultimately allows your friends to take the kills but you getting from around 20 -40 points for each one killed during the attack. It also takes long to reload ( Longer than the sawed off).
Tomahawk: you only get one if picked up, has long range and it is pretty fast. If it hits the head it is a instant kill yet any where else half your health goes.
Disruptor: Can only be used in close range and 2 ammo capacity and it jams any gun that the enemies have to reload lie a failed reload.
You guys might think these are to overpowered just say if there cold be any changes.