What i meant is that you should still hit markers at 25meters like 1 shot kill at up to 10meters the a 2shot kill at up to 15meters and a 3 shot kill at up to 20meters
Not every weapon needs to perform awesomely everywhere. Shotguns do very well in a niche role. If you want to play with them more frequently (and do well), play the Devastation DLC playlists; Behemoth seems like a map custom made for shotguns.
Alternatively, play Hardcore. Put slug rounds and a red dot sight on a Bulldog. Realize that you've just created a sniper rifle with a red dot sight and almost no idle sway. Laugh maniacally. Go tear shit up.