Ah, but what about Kamovs?
When both rotors are on the same shaft, one above the other, applying different cyclic to both would serve only to bend the shaft (or if you're really out of luck, the tips would touch).
Being on the same shaft and generating equal amounts of lift and torque, they normally cancel each other out. When you want to turn on your axis, pressing, say, left pedal reduces the pitch on the anti-clockwise rotor and increases it on the clockwise rotor - result, fuselage turns anti-clockwise, or 'left'.