I agree we've gone as far as we can with what we know.However,training issues havent really surfaced.Full stalls are trained in flight school.In airlines,only the approach to stall is trained and minimum altitude loss is always emphasized.This might lead to a dangerous mindset for newish pilots;the altitude loss is as important as recovery.Significant altitude loss is a dead cert at altitude.High altitude upset recovery also rarely trained.Other training issues that I can think of;crews anxiety over busting altitude when facing speed loss at altitude.Crews have been known to wait for ATC clearance before descending.Turn off airway and DESCEND IMMEDIATELY.The use of weather radar has been addressed but they knew there was weather up ahead.Tilt,gain and brightness control are possible traps.Captain's rest already discussed.
Combine the gaps in training with airline-endorsed automation reliance and the peculiarities of the Airbus and you have enough ammunition to establish a strong case for pilot error with strong and genuine mitigating circs.