While the master traits for AoMr still require taking Dualgunner, such a powerup would really make people doing a pistol run on other modes angry if they had just taken Dualgunner before finding the powerup.
So, yeah, I'm against.
New Item Time:
Spinner Blade
"Where the hell is this from?"
Inventory: A bladed... boomerang? Sure, whatever.
Accuracy: +4
Damage: (2d6)x2
Throw Time: 1.2 sec
Damage Type: Physical
Special: Goes between Player and Range of Vision, hitting anything on the aiming line. More useful against crowds than single enemies. If it's at the edge of the Range of Vision, it only gets hit once. Returns once thrown.