Buzz, the thought #1112 was not intended to imply anything; certainly not right or wrong. The objective was to reflect on the general uncertainty and judgement required in aviation, including certification.
Assuming that the nuances of the GA mode were fully appreciated during certification (was this the flt test or the operational evaluation team), then the certification is based on the judgement of skill, alertness, safety, and acceptable characteristics. This opinion was most likely based on experiences and standards at that time, and where projecting this over the lifetime of the aircraft type would be extremely difficult.
Certification judgement remains a 'dark art'; any one view is unlikely to represent a world wide standard, nor accommodate changing standards overtime. Thus even though an aircraft has been certificated, certain aspects are open ended, based on assumptions which may longer hold true.
What operators lack is a clear explanation of what assumptions have been made during certification (skill, knowledge, workload, etc), i.e. operators lack guidance for determining procedures and training requirements. Also, any assumption has to be balanced by the likely human performance in a range of situations, not all of which can be foreseen.
It's all very well for NTSB to ask FAA/Boeing to review system designs, but unless there is a clearly defined standard for judgement, then the industry should not be surprised by a conclusion "that the system was alright then, so it's all right now".
This issue represents the growing gap between 'flying as imagined' at the time of certification and how flying actually takes place today; the regulators have to appreciate changes in the industry and avoid resorting to 'more training' for systems knowledge and awareness, where human limitations in memory and recall associated with these factors probably contributed to the problem.
You cannot expect to solve a problem with the same features which contribute to it.