In other words, a design which requires roll inputs, is going to get some pitch inputs, like it or not, with a normal pilot - add in the surprise factor, turbulance, lack of high alt hand-flying training etc. etc. and this can all add to the amplitude of the pitch inputs, which seem to have been unrecognised by the PF, and the lack of recognition then caused the long duration of that NU input (which, integrated over time, drove the THS movement).
A key element of manual instrument flying is building a mental picture of what the instruments are telling you and then controlling the aircraft with that information. With a PFD, it is much easier than with steam gauges since the majority of data is in a narrow visual span.
My present conclusion regarding the PF's control problems is that his scan was broken and disfunctional. His problems were very likely compounded by an inappropriate grip of the stick from the start, i.e. palm instead of finger tips.
The core of a manual instrument scan is control of the nose attitude and roll attitude-just put the pipper above the horizon line by the appropriate amount (~3 degrees in this case) and level the wings. Then drag in peripheral data from the sides, altitude, heading, and airspeed. Make small corrections as necessary. In the case of AF447, since airspeed was not available, apply suitable power to ensure stable speed.
In just a few minutes of this tedious flying, they would have been well down the road and away from the weather-but this did not happen.
Altitude never entered the scan, nose attitude did not enter (or else an inappropriate response to earlier training did). All the PF's attention appears to have been centered on controlling roll attitude which he was badly overcontrolling.
I can see two approaches to preventing this type of accident.
1. Provide a wing leveler function in Alt 2 law so the PF doesn't have to touch the stick except to maneuver. (The lowest common denominator approach)
2. Emphasize basic manual instrument skills under worst case conditions during recurrent training e.g. flying the S-1 and S-3 basic instrument patterns (by hand of course) at altitude in Alt 2 law. (You can always ask to try flying this just to prove to yourself that you can still do it.
)
I am hoping the regulators mandate the second approach.