Lyman, before you go traipsing too far off into engineering La La Land, let me point out that the aircraft control systems were functioning as designed later in the flight, that the control gains were designed to be appropriate for that portion of the flight envelope and the aircraft was well inside its envelope, and the decision by the engineers was sensible since in Alternate 2 law, the aircraft did not require using as many spoilers based on actual flight tests results and calculations of spoiler effect on wing bending moments.
There is plenty of evidence to explain the performance of the aircraft as the effect of turbulence and pilot control inputs.
Take a look at the Cooper-Harper pilot rating scale located here:
fig66
If you were to ask PF right then about flying qualities, he would have been in the 8 or 9 area, but in retrospect we can assign it a 10 (because he lost the plot in pitch)
(rudderrudderrat has the idea.)
Right about now, I anticipate that all the experienced Airbus drivers will have their hackles up and snorting a loud "Bull Sh&t." "I've flown in those conditions and you just have to be gentle with it." And you would be 100% correct. The problem is that PF had never been trained for that corner of the flight envelope and started off on the wrong foot with it. To be specific, he used an improper control strategy. That was the beginning of the end for AF447. There was time to save the day later, but by then, the crew was too rattled to work their way out of the situation.
At least, that is my take on the HF side of this accident.