Simplicity
I've read most of the AF447 threads and I am quite surprised by one thing:
Regardless of complexity of the situation with crew been hit by many confusing alerts, flying in the darkness without visual reference, did they doubt about indicators of altitude and vertical speed? (I don't think so, CVR revealed it).
What else than lack of lift => lack of speed can cause falling that bird so fast from the sky? Did they believe that they are in a dive/overspeed situation?
It seems to me that flying modern a/c (plus training) went too far away from simplicity. There are some senior data applicable to airmanship and if they are forgotten then gross piloting errors are the result.
It seems to me that the very basic principles may be neglected in training and too much attention is given to various particular issues which are rendered unimportant once basic skills are out.