Originally Posted by PJ2
A third possibility, (perhaps a sub-possibility from either of the two above that you've mentioned), may be the PF's relative inexperience with high altitude manual flight, (in Alt 2 Law, roll is more sensitive than pitch), resulting in an unintended stronger pull on the stick than he desired, which he then began wrestling with at the same time he wrestled with (and nicely got under control) the roll oscillations. The two "stall warning" blips surprised both crew members, (What was that? - PM), but of course both warnings were legitimate as the AoA for the ECAM Stall Warning had been momentarily exceeded. Subsequent stick and pitch actions are less understandable but obviously plausible to the crew. Why?
PJ2
You will get no argument from me here although IMHO this belongs under (2)-They lost track of the aircraft due to roll control problems.
(in Alt 2 Law, roll is more sensitive than pitch)
Your observation on the force mis-match between proper pitch and roll inputs is significant from an aircraft handling POV. This is an undesirable combination.