Of course you are right, I shouldn't have used the bad "r..." word in that context. It's only useful to upset people around here.
The behaviour of shotguns in 7d2d is just as realistic as it is to live in the zombie apocalypse, carrying a self-constructed motorbike whilst climbing a ladder, not to forget the 6000m³ of wet concrete mix...amongst other things of course.
Well we have zombie ants.... soooo....
but seriously. you can make game "realistic" - like assasin creed. ( this is just like style - bordelands have comics style, loop hero have " 16 bit console style", far cry have black comedy style etc.)
NZA is good example for this ( because it use system + assets from V2)- you have realistic soldiers uniforms, tanks, things in bunkers , logical bases. Then are "fantasy" things like zombies occult stuff etc. ofc things can be chang to more suit into gameplay that's true but you can still keep "realism" like : mp40 have 32 magasine, sdk using mg42, vikings don't have helmets.
So that's why devs spends so much time looking how bulding was looking in XV century, what people was wearing etc. Assasin screed can be good example - in ac1 they wanted to give altair crossbow but artists say it would unrealistic because crossbow wasn't used in this period and in this same time add alien tech.
So let say - realistic can be "artist" style - plague tale is realistic or horizon zero dawn or origins.
Autentic is diffrent style - red orchestra, heart of iron , let hell loose or sturmovik.
so i will give you example ( WARNING! NOW DON'T MATTER IF THIS WOULD BE ADDED IN 7DTD OR NOT THIS IS JUST EXAMPLE HOW THIS WORK)
So let say - someone suggest change ak47 into m16 because usa military use more m16 - this is realistic idea
another person suggest change m60 bullet types because m60 don't use this same bullet time as ak 47 - this is autentic idea.
so "realism " shotguns could works if guns woudn't be connected with perks - so shotguns could works that way in let say - l4d2 or in contagion.