I think its more about getting used to the Shotgun, I Find the Ahnuld-12 to be really powerful and do really well with it, But give me any other shotgun and watch me suck :<
Aiming for the Head is ofc the most important thing with this shotgun, if your shooting body shots you will not do very well a Headshot mid/close range can take out a proxy/Aura in one shot and pretty much disable any other heavy class.
But to be completely honest with Fletcher you should be using the sticky’s way more then the shotgun. (Weaken the enemy then finish off with shotty)
A Neat trick i have been doing is: Throwing a sticky at an enemy and then shooting the sticky on the enemy’s body.
Overall it seems like people are complaining on the forums that Fletcher is weak and calling him Op in game :3
Secondary wise the Empire-9 I kinda hate it and rarely even use it, i would have to be out of Sticky and have no loaded shells to even think of using it >.<. I dont find it too reliable as it tends to stick in the heat of battle(Switching and trying to fire in quick succession and the it seems to not fire half the time)