Add body armor plates for Assault class, but make it a gadget they can deploy. Each pack has 4 plates, once used it disappears. Each plate grants 3 hits of damage reduction to the torso. After that the armor plate breaks. This gadget replaces the ammo pack, and can only deploy one per restock. This makes the player choose between ammo and survivability. If a nerf is needed, armor plates can slow player move speed.