I think deep stall is a thread drift. There's another stall on highly swept supersonic fighter like the Russian MiG-21, the super stall where it's not possible to power out with full power and after burner unless the AoA is reduced. It causes significant loss of altitude.There's nothing like that on Airbus 320/330. What can happen to most commercial aircraft is incipient stall or fully stalled. AF447 was not on the verge of stall but taken well beyond that and held there in fully stalled state. There were 24000 posts on AF447. You can't chew it anymore. The courts will decide if at all, whether the training syllabus of the manufacturer sufficiently covered unreliable airspeed and stall recovery and for Air France part did they train their pilots accordingly.