ok so im not a really big fan of them but i do like them so i have some compromises for their very short range.
1. they have a constant tight spread 2. the bullets have no drop off( in its range always a one shot kill) 3. scopes/sights increase effective range of shotguns 4. they can shoot slugs( very low damage at range, within the shotguns pellets range is a one hit kill anywhere) adds diversity to the class to make them usable out to medium and possibly long ranges. 5. the extended mags should give them more pellets per shot( 50-100%) like it did in mw3 before the patch.
the under barrel shotgun should have the longest range of the shotgun and be semi auto( it is very low in damage 4-5 shots to kill but has a fast firing rate)