Now why should a shotgun be less effective damage-wise beyond point-blank range? It's not like the content of the shell would magically lose 90% of it's kinetic energy or firepower when it travels beyond 10ft distance.
Because they aren't firing slugs, as the firing pattern clearly shows. And we're not talking 10 ft here. We're talking 50+ feet where a single speck of buckshot will drop a clot. I don't expect it to be completely gimped at range...but I do expect it to be somewhat less effective than a rifle. Then again, the damage bonus on perks makes it pretty hard to have anything seem realistically balanced.
I just don't think Shotguns should be long range hallway sweepers. The damage value should fall off a lot more significantly than it does now.