Humm....
First off there is yet to be a solid measurement for stiffness. So words alone don't do it justice in comparing one frame to another, its a one persons personal feel and preferences over another's. There needs to be an outright measurement(s) to get to a solid comparison of stiffness of a frame. It may not determine which is the best frame but will give us a measurement to use to allow the user to pick what they deem best for them under their riding preferences and use. Much like geometry where some custom bikes allow well custom geometry's for a custom fit, we could have a custom stiffness setting for a custom stiffness fit/feel, even if its just material(s) feel for the rider.
I know if there is such a measurement the industry will use it incorrectly in a way to brag how stiff their frame is, even though I doubt its what most riders would want, but there will be buyers for it as wrong as it may be.