User blog comment:Bovell/Kotaku claims to have MW3's first look. Robert Bowling responds. (Minor spoilers)/@comment-93.138.175.63-20110514191926/@comment-24.208.161.23-20110514204517

Because shotguns in MW2 were made to be primary weapons but at the last second got put in the secondary weapon list and they didn't change any of there stats. That is why all the shotguns were better as secondaries than any of the other game were they were primaries.