If the regular shotguns weren't so utterly cucked by armor and weird spread mechanics, they would be decent weapons for the current vet paradigm.
Shotguns have actually always been goated for Vets, the problem is that weapon specialist makes them a lot more effort to work than they really need to be, plus they are incredibly ammo hungry. The recent balance change makes them even better, but the ammo problem persists. In general, a lot more guns would be viable if they were not absurdly ammo pack dependent when everyone needs to share ammo pickups.
Sadly though I don't think anything can save the double barrel, it's a meme weapon but it's spread and falloff is embarrassing to the point where it's just another melee weapon heavy attack you whip out with the free bullet reload perk.
I will defend the vigilant autogun, though.
One of them.
Cant remember the exact model, but I made a Vigilant build that was actually incredibly good.
Hit the breakpoint to 1 shot Any non-carapace enemy in 1 shot and would 1 shot body any flak armored enemies, and could melt bosses if you could land the shots because it abused the multiplicative headshot bonus (1 bullet = 1/6th beast of nurgle hp kind of deal). It was a pretty fun build (especially with the autotrigger mod, since it converts it from a tap-fire into a HEAVY autogun) tbh, but the problem was it relied on actually being a good shot and keeping sharpshooter stacks up which is a dogshit mechanic to play around. The stupid irony of sharpshooter especialy is the stacks stay on headshot regardless of momentum, which makes it a better tree for the SMG Autoguns/Scout Lasgun since you will accidentally get headshots while hosing anyway, you know the exact opposite of sharpshooting.
I mentioned snipers, specifically because they need to dethrone the revolver as a do-it all specialist killing tool. I have a burning hatred for the revolver. It wouldn't be so bad if Carapace stopped it in it's tracks but it straight up ignores it.
It's one of those guns I feel is just too good at everything, for any class that can use it.