It is my understanding that helicopter blades are negatively twisted starting at the root with the greatest static pitch to the blade tip which is usually at zero or near zero AOA relative to the basic low collective static position. The purpose of the twist is to attempt to equalize the lift across the blade span to minimize blade bending during flight.
With active blade twist this fixed relationship between the root and the tip would be constantly changing developing a very strong traveling wave from the tip to the root requiring some very heavy vibration damping gear on the head. It might also lead to serious fatigue problems due to the traveling wave both on the blade and at the root attachment to the rotorhead.
But then again I’m not a graduate engineer just a fat kid from Cleveland.
