Many thanks to all those who have replied: as I stated at the beginning, I have formed an interest in this subject as applied to the PPL examinations, and the question of how instructors and examiners discern a worthwhile candidate. (Allied to this is how much trust do other pilots in general repose in a new pilot trained under the present regime.)
Additionally, some of the replies have started me thinking along the lines of where congruence between flying training may exist with one of my professional activities.
Could it not be the case that a candidate who cannot express himself well, and logically, on paper is unlikely to be able effectively to communicate in a stressful situation? These are the kind of criteria I apply in one of my professional tasks, when recruiting, for example. (An ill-expressed, misspelt, ungrammatical CV would not receive a second look.) I only ask in order to stimulate further debate, since I am not sure how far using that activity as a metaphor for flying training is valid.
Perhaps the idea of a second Air Law examination, at a later stage of training (or perhaps as part of the IMCR ground requirements) should be an essay-type arguing an appropriate response to a hypothetical difficult or dangerous situation?