They're an embarrassment to the shooter genre. Miss by 1cm multiple times and you will not kill your target. Seriously, where is the bullet spread? It is not realistic in the slightest to have the trajectory so tightly packed.
Just like the first game, shotguns have 0 spread.
Shotguns are made to increase hit probability while still being lethal (i.e. deliver multiple pellets ont the target) while minimising collateral damage.
Shotguns in CoD are typically balanced in a way they work more like a breaching load and CQB while realism is completely elsewhere :3