Winchester City Killer is a functional design and in-line with how early Fallout portrayed fictional firearms. "Combat Shotgun" from Fallout 3 is a result of someone not knowing how firearms work, taking a look at a PPSh, and proclaiming "Yup, that's a shotgun!" At least the G3 and AK Chinese Assault Rifle make sense, even if the latter seems to be bastardized as well, but to your average normalfag at least it looks like an AK.
This is more a symptom of Bethesda's retarded gun logic, or lack there of due to them not knowing how it works. When they were in charge of designing every single gun in Starfield, EVERY firearm is now a Combat Shotgun tier abomination. Even real world based "Old Earth" firearms are abominations. I suggest looking at the above Starfield video, it goes in-depth on how these guns should not exist, and how they COULD be fixed to be functional fictional firearms. There really is no excuse.