What can be changed assist in avoiding this kind of accident?
This is a very long thread now. I am perhaps foolish to add to it further, but here goes...
It is clear that the pilots on the day (or night) were indeed idiots. However, I think it is fair to say that we are all capable of being idiots on our day also. It is desirable but impossible to assure that every person has the complete skill set or training to deal with every eventuallity.
Therefore, I think that even though working on better training and weeding out bad pilots is of some assistance it will never be able to ensure all pilots are adequate, properly trained, or will not have lapses in there handling of situations.
Notwithstanding the above, I think there are two things that could and should be changed that may well have given the crew assistance.
First, when the autopilot disengaged there should have been an explicit message that it did so because of air speed indication anomalies.
Second, clearly the stall warning should continue regardless of airspeed except in specific circumstances ie if you are airborn at significant altitude there really is no reason for the stall warning to be discontinued...
These matters are easily corrected and are clear failures in logic. No one will ever know if these changes would have saved the fateful flight but I am sure that they would have been of some assistance in overcoming the confused state that the pilots had fallen into.
In addition, "Pull up...Pull up" was perhaps not as helpfull as it could have been in that it was exorting the pilots to do exactly the opposite to that which they needed to do. It was in the event less helpful than "don't crash...don't crash" would have been. What it was really trying to say was that they were loosing altitude and getting close to the ground.
A careful review of the messaging that pilot get is needed in order to at least avoid ones that are not helpful and ensure that helpful ones are not disabled.