I can't comment on the technical aspects of differing stall recovery techniques, but I will comment on the human factors element of this accident.
It seems to be quite clear that the candidates were not comfortable with the test environment, whether that was due to IMC or the test regime we don't know, I'd suspect a touch of both. I would question the judgement of the commander and to a lessor extent, the examiner in this instance, it must have been obvious that the candidate was stressed, why push it further?
It stinks of either get it done-itis or macho flying imho. A needless accident.