The Stall
The application of rudder for stall recovery is not to prevent further 'wing drop' but to prevent FURTHER YAW!
Having recovered from a stall and speed gained the wings should be levelled with the horizon BEFORE adopting the climb.
I too have my students maintain the aircraft in the stall in order that they have the full knowledge of the symtoms of the stall and the characteristics of their particular aeroplane during the stall. They will then better understand the actions that are required for recovery ie; the 'standard stall recovery' as we know it modified for the best action for a particular type.
Throughout all stall training emphasis must be on relaxing the student and removing fear. Fright and ignorance being their biggest hazard which will most likely to lead to an unsuccessful recovery when it matters.
I cannot understand how a properly conducted lesson should lead to an unrecoverable spin.