Warning or Instruction
Approaching a stall a warning is announced: stall, stall. Would it not be better if an instruction were given: stick forward, nose down.
Also, had the AoA been prominently displayed, the PIC of AF447 would have surely seen the problem immediately he returned.
I know nothing about flying an airliner, but I would expect the PIC to take control of any aircraft that was out of control. He knew the engines were operating and the aircraft was sinking at 10,000ft/min. Did he not think he could do better?
No doubt plenty could be said about training and recruitment but this much seems obvious to me.