They should have been more like the shotguns of MW2. Instead the developers nerfed the minimum damage for all of them which dramatically decreased their effectiveness. I would have honestly preferred they stayed as secondaries even if they were overpowered (they weren't that overpowered) and anyway... there's no reason to use a shotgun as a primary weapon if you can have an assault rifle with a shotgun attachment and be better off for it. Thankfully though Black Ops II is changing this with the Pick Ten system. Though it would have been nice if they'd implemented more shotguns.