NB : This post is intended as summary only - as PJ2 says, the arguments were exhaustively played out over 11 threads in Tech Log.
@Sunfish - This was not a complex or unforeseen failure mode. Unreliable Airspeed Indication causes a drop to Alternate Law, which has no hard protections. This was well-understood by all the engineers, and if it was not communicated to line pilots, it should have been. We know Airbus sent out a bulletin describing a workaround procedure while the problematic pitot tubes were being replaced. How well this was disseminated by airlines amongst their crews is less certain, but we do know that over 30 UAS incidents occurred before AF447, and all of them were successfully resolved by their crews.
@AZR - I don't know for certain, but an educated guess says that NCD on a T7 will cause stall warning to cut out, because with no valid data, the stall warning subsystem has nothing to work with.