I agree the Wilson "sound" is excellent, right up there with the best I've heard.
I agree. FWIW: Rigid Metal or Ceramic woofers are often used in high end systems and people love them and buy them (lightweight "piston" operation means small low cost motors, such as 1 inch voice coils, can be used and they are efficient and very linear in response).
However these designs ALL have ringing problems! Why else do manufacurers use sharp Q notch filters to dampen ringing and why else do some use two rubber dampers on the edges of the driver cone. Why else do paper/pulp/polypropelene and woven and doped kevlar designs exist...these less stiff designs offer better internal damping - less ringing - even if they are less ideal "pistonic" (and generally require an expensive larger voice coil for better diaphragm support)!
Speaker design is often a compromise...thats all. However, I'd be wary of this particular tweet - note that it is used extensively in another highly regarded manufacurers speakers ...so perhaps the other manufacturer deals with the ringing problem more effectively in their crossover design.