Calls to close threads are like closing the mind.
Final reports can be used as definitive understanding, generally they are very good, but can be biased by a range of factors. Some reports find 'most likely' causes, others contributing factors, all with significant supposition about human behaviour; uncertainty.
We take from that what we wish to believe, we might learn, and with closure not open to further learning.
There are several issues relating to this accident which with debate could benefit safety. They are not definitive or proven; just some of the everyday uncertainties which everyone experiences.
There were 20 or so previous incidents which crews successfully managed. Anecdotal evidence suggests that some crews reacted initially as AF 447, but subsequently change their course off action - why.
There are no simple answers, if any at all; just opportunity to think.
Bad apple theory, unproven and least helpful.
Situational factors more likely, levels of experience, but what experience, how gained.
Differences in training - some operators require Captains to fly the aircraft during emergencies; do relief pilots ever experience flight in abnormal conditions, degraded control systems.
Does recurrent training consider the 'do nothing' option of the drill required for the cruise situation.
Do regulators mandate more recurrent training for new threat situations, but what was the threat. 'The pilots' - using SOPs, or 'ice crystals' which should be avoided.
Safety-I vs Safety-II viewpoint, the human as a hazard, or the human a help to avoid a threat.
There is no need for the above to be proven; the safety value is in the thinking about them, which might be greater than in any final report.