Thrust, trim control attitude, airmanship, lack of airmanship, recognizing the failures etc.
All valid points, but it comes to knowing what they were doing and what to expect, if they had ONLY calculated the minimum speed for the conditions of the test like the Airbus Test Pilots do and NEVER go below it, they would have never needed any of that.
They were not prepared and more important, they were not familiar with the test and how to avoid trouble if the test was not successful.
G