I was surprised to read in airbus Safety First December 2007 issue a detailed discussion about Unreliable Speed, exactly one and half years before AF447. It included Effects and consequences in the cockpit, Identification and handling of UAR situations, Procedures and BUSS. It didn't seem to have caught anybody's fancy. The crew that night was simply ambushed. It is amply clear that they didn't have the knowledge or training to identify what was happening and apply appropriate procedure. UAR is very serious situation to identify and correct and in my opinion something that was not going to happen by accident. In a habitat that is not human confronted with a situation you feel inadequate can trigger extreme fear leading to hyperventilation which can wipe any semblance of rational thought. What difference another instrument would have made is impossible to predict. Airbus did give a thought to AOA indicator but didn't consider favourably. In a conference in 2010 airbus had stated the following:
Even if the AOA is the key parameter, we do not intend to equip our aircraft with AOA indicator for 2 reasons: first this would require a specific training, and second the stall AOA varies from low to high Mach number so that it is not a constant value.