Novel situation
Lonewolf_50, I would go with the novel situation idea.
After all, given how much has been done to eliminate accidents, most common situations that would lead to accidents are going to be covered off by pilot training and experience, aircraft design, etc. I suppose a pilot could make a "rookie mistake" and in some situations that could cause a crash. But these days most crashes are likely to involve a confluence of different factors that if they had not combined wouldn't each have by themselves resulted in a crash. It is likely to be a novel situation.
I suppose one implication might be to add something to basic pilot training. Try to also have training to help pilots to recognize and deal with novel situations. (Aside, pilots who flew in wars might, besides having just more experience, also have had to develop more ability to deal with novel situations.)
Even though a situation might be novel, the pilot's ability to deal with it is still going to be affected by the way the aircrafts instrumentation and systems work. How much useful information did the pilots of AF447 get? What were they able to do to command the aircraft? We really still have to go to those factors as the underlying "fault". Unless pilot qualifications start taking into account the person's ability to deal with novel situations, blaming it on a novel situation isn't all that helpful. Even though, yes, it was a novel situation.
Like others, I'm puzzled about what happened during the final 3 minutes or so, and why there is so far no information about that. I find it unlikely that all three pilots were stunned and baffled and just did nothing. Unless maybe the physics of the situation made it impossible for them to do anything? Otherwise it is likely that one of them at least tried to do something to save the plane and their lives.