Willow. Thanks, #672 . Re
'average pilot'.
Although there are some documents which refer to an average pilot, the term is meaningless in safety regulation.
There should be no statistically below average pilots flying an aircraft assessed as suitable for 'an average' pilot.
Children of Lake Wobegon;
https://psychology.wikia.org/wiki/Lake_Wobegon_effect
The regulations relating to flight crew action are based on qualitative assessment - expert judgement; i.e.
"…
a potential failure condition can be alleviated or overcome during the time available without jeopardizing other safety-related flightcrew tasks and without requiring exceptional pilot skill or strength," AC 25.1309
"…
provided overall flight crew workload during the time available to perform them is not excessive and they do not require exceptional pilot skill or strength. Unless flight crew actions are accepted as normal airmanship, they should be described in the approved Aeroplane Flight Manual. ' CS AC 25.1309
Boeing's certification failures were in the issues above; misjudging human capability, task, and nature of malfunction without any safety margin.
The FAA's failures similarly misjudged the human aspects, also with limited oversight of Boeing tacitly agreeing with their view..
The differences now required by EASA and Canada highlight this; whilst their changes are a polite, public view, the regulatory view is more 'a judgement too close to the limit - OK now, but not a precedent'; which in non-regulatory terms; you've still got it (judgement) wrong.