They're actually already the same thing functionally to DPS. Open cover (probably non-cover and non-negative ground) is 1.25 accuracy and damage, negative cover is 1.25 accuracy and damage. Negative cover's difference is 1.5 suppression over open's 1.
redesign cover. All open ground is now red cover and you receive bonus dmg and suppression. New system any units that are not vehicles suffer shared bonus dmg from small arms fire.
often volks, rifles, or guards will have a unit or 2 soaking up dmg while the rest pop back if they're charging as a group.
the idea is if a bullet misses, it will hit the guy behind you or next to you.