I think maybe a THIRD accident pattern is being mixed in here, too. There were some accidents in SxS Air Commands in Engalnd the late 80's. These were almost certainly PPOs, but the concept of PPO was locked inside just a few people's heads at the time.
The investigators (incorrectly, I think) blamed "pump handle" joysticks (those with a pitch pivot at the rear of the seat), among other things. The Florida owners of Air Command at the time came out with an "A.D." requiring a swap-out of the original aluminum pump-handle Air Command joystick for a Brock-style steel, walking-beam stick assembly designed (I believe) by Bill Parsons.
The PRA gyro design guidelines followed suit. For many years, they recommended avoiding pump sticks. They may still say that. It's a silly distraction from the real causes of PPO, which are mainly airframe and tail-feather layout.
As for aluminum sticks a la the original Air Command, I see nothing wrong with a properly-designed one on a light single-place gyro. Both Bensen's original overhead stick and his later, B-80 series joysticks, were built this way. I agree that one does not belong on a 1500 lb. machine unless the stick is much more heavily built that the typical 1" x.058-wall 6061-T6 tube used on light machines.
Back to topic: Some early Dragon Wings blades had just about no reflex (up-turned trailing edge) at all. Since their particular airfoil shape places the camber back from the leading edge compared to flat-bottomed foils, they have less need for reflex than the flat jobs. In most cases, the structural stiffness of the blades themselves is sufficent to resist twisting, even without any reflex.
The twisting moment is variable, though (it's a function of the square of the blade's airspeed, and that in turn is a function of both the gyro's own airspeed and RRPM). If the blades develop too much twisting moment on the advancing side (where their airspeed is the highest), the blades will de-pitch themselves in that sector of the rotor. The rotor's AOA will start to flatten out on its own. The effect is similar to hard forward stick -- a dive. That's likely what happened to Jamie Bodie and Sy Smith in the heavy Marchetti at Mentone.