Interesting. Assuming that a) riders weren't being completely random; and b) they were comparing relative comments by the same rider to avoid one man's noodle being another's... umm... very stiff thing...
... then it would be fascinating to know what is associated to the perception of noodliness.
The vagaries of human perception. How do you account for the fact that so many people claim that Ksyriums are stiff wheels?
Here's a tangential issue: if you look at the rolling resistances for tyres, listed as Watts dissipated at 30km/h, the difference between a good clincher and a good tubular is of similar order to the difference between aero's of eg a deep-dish wheel and a Ksyrium... at 50km/h.
So setting aside time trials, the RR should be much more important than aero effects, since riding in a pack at 45-50km/h will generate the RR corresponding to 45-50km/h, but the aero drag of a lower speed because of the bunch effect. The aero drag roughly halves going from 50 -> 30km/h.
I think you've over simplified things a bit. You presume a given RR and a given drag, but those things aren't given. Also, it is not conclusive that clinchers in fact have a better RR in all given conditions. So far, the data points that way; however, the data has not necessarily been collected in a way that accounts for varying operating conditions. So, it's a mistake to make that assumption. It is known, however, that aero factors dominate over about 15mph (24kph). Also, you've forgotten that aero drag is quadratic with velocity whereas rolling resistance is only linear. You're assuming that RR overtakes aero at some point in your model, and that cannot be assumed. You need to account for initial conditions, i.e. actual drag numbers, RR numbers, etc.
Ergo, most of the pro's should be on clinchers most of the time. The fact that they're not, suggests that something else is playing a role, which is presumably bigger than both aero's and RR. Could it be dissipation via flex?
your assumptions are correct, there is still a lot that is not accounted for. It's doubtful that wheel flex accounts for any significant energy loss at all, given the very tiny amount of frontal deflection any wheel demonstrates. And in a pack, it's unlikely that there's any significant lateral flex. There's really nothing empirical to suggest that a wheel's hysteresis in lateral flex is significant in the pack. The greatest lateral loads are in sprinting, entering a corner, exiting a corner under power, and also in the case where a wheel might hit a large obstruction.