DeltaFree,
You are correct. If, or as, this concept is developed for faster and faster flight, the whole rotor assembly, including blades, will require higher levels of rigidity.
ShyTorque,
This concept is based on the principle that the blade tips and the blade roots have separate pitch controls (say separate swashplates).
This is an oversimplification, but may help in grasping the principle;
In forward flight, on the advancing side, the pitch of tip and the root are the same. In forward flight, on the retreating side, the pitch of the tip will be positive (upward, as is conventional) but the pitch of the root will be negative. It is negative so that the reverse airflow over the root will provide lift as well.
As mu [forward velocity / tip velocity] increases, the location on the retreating blade which experiences no airflow will move outward towards the tip. At mu => 1 the whole blade, at 270-degrees azimuth, will be in reverse airflow. Therefor at mu=>1 the whole blade, at 270-degrees azimuth, will have negative pitch.
IMHO
Dave J.