Can we Please!!!!!!

I get what you mean, but shotguns probably aren’t the main issue. Most of those long-range one-shots are from players using slug rounds, not normal buckshot. Slugs hit hard but are slow basically like a short-range sniper bullet. They reward precision, so when someone lands one from 45-80m or what ever, it looks broken, but it’s more about accuracy and timing than the gun being overpowered.
its similar to real-world but still not as powerful. 
I do agree it could use more flinching  when hit  though

Can we get Flinching please. 

No, we really can't. 

As someone though who hunts with slugs in a shotgun you still can't shoot that far with them.  

I agree with flinching.

It makes sense in its own right, but with the awful near-useless implementation of suppression in this game it is doubly important.

There's basically no point in trying to counter snipe a sniper with anything but another sniper with this suppression. Anything else just gets you headshot because you can hit them 3 times in the head from range with say an LMG and they will just calming pull off a one-hit-kill headshot in return.

One shot distance is over the top atm. No denying it.

Shotguns do not need any more of a nerf than they have already got. SMG are still better in almost every case.