Well I think some people should get their hands on some playtime before saying there should be things added or taken out.
Although the guns in the game are based off of real life arms, they dont need to be/or have to be the embodiment of what they are in other games (cs:go) or their real life counterpart.
The way it is they seem to take the nuances of what each gun is and put them in the game in a balanced fashion. The highest damage ARs have slightly recoil and a lower rate of fire, than their faster firing a less recoiling counterparts. I would imagine DPS is about the same but they fit different play styles and mercs. This is a game more about movement and team play than weapon mechanics and learning recoil patterns.
Im not sure how shotguns work right now as i havnt played them enough but i like how they were in ET:QW. IIRC it shot 9 pellets in a random cone, each pellet did 10 damage for a total of 90 damage total per blast, if they all hit. BUT, it didnt matter where it hit on the body, it was always 10 damage, no extra for headshots, no less for arms or legs. This seemed perfect as you never got obliterated in one shot going around a corner and yet it still did a lot of damage. That game only had 1 shotgun type weapon per side so ti was a little easier but still food for thought.
Just dont put in a 1 shot (non headshot) kill awp weapon.