Yeah In the blood angel codex it says strength 4 in the summary... A unit of 10 scouts assaulting in the first turn all with S4 two times before combat would be nice.
I guess you're right.... If you have a squad you use them for one purpose and not multi-tasking...Well now you;re talking about two entirely different squads.
You should compare apples to apples. In this case, shotguns should be compared to pistol & CCW since they're both assault-oriented loadouts.
Snipers are fine and dandy, but you use them for entirely different purposes than shotguns or pistols. Nobody is suggesting using shotguns as a long range fire-team.