This is exactly what i was saying from the release of the game to December when DLC came out. They're extremely powerful if used on enemies that are already in your face (like a surprise Minoturd in VoG for example), especially the ones with fast fire rate (for maximum stun capabilities) and 6 rounds mag. Nightfall is the only content in the game i wouldn't suggest using a shotty because.... well, its kinda obvious but its better not be in the melee range EVER.