I have Diamond shotguns on the WIIU version. I play shotguns mainly (either shotguns or pistols)
I can honestly say that shotguns in general are NOT overpowered.
There are honestly so many ways to counter a shotgun user. Sure, they're a pain when you don't expect them but they're limited and usually go on the same route (allyways, small rooms, corridors)
BO2 is a CQC game and as such you should naturally expect CQC duals.
Remmy: By far the most 'noobiest' shotgun. It has a far OKHO range and it can be used by noobs, which makes it deadly.
Ksg: Have you even used it? Try to get it gold and you'll see this lovely hitmarker machine. Sure, it has a long range but use it for more than one game and you'll come back trying wanting it to be buffed.
M1216: Deadly at closerange but it sucks at mid-range. This isn't used by noobs because you have to time the reloads.
S12: It's a beast for multi-kills, on 1v1 encounters it's quite a pain (unless you can trigger it quickly)
I hate it when you guys cry that shotguns are overpowered. Seriously, get a life and learn how to counter them. I find it hypocritical that you moan about them when you yourself are probably using an SMG (PDW) with a silencer on every single map.
The thing about shotgun users is that they die shortly after they kill (unless you're facing a pro shotgun user). He may get 2-4 kills before he dies and they usually have a 1kd. This means that they are limited to scorestreaks and NEVER end up getting anything more than a wartog (not from what I have seen).
Let's compare this with a SMG user, not only do they have range. They have a lot of ammo and flexability. How often do you see these SMG 'pro's use higher end scorestreaks? I personally find them quite often (either SMG or Assault rushers)
So, who is OP
Think about it and stop complaining.