Of course stall warning does come from the AoA sensors. What I'm saying is that if the AoA sensors are below the range where they give accurate readings then the stall warning should be sounding.
So now, when the pitot tubes ice up (as they did) and the CAS drops off (or any other ADR fault) you want the crew to be distracted by a constant blaring Stall warning - that no matter what you do with the aircraft (pull, push) - keeps sounding? This is a major design philosophy that when a sensor output fails or is deemed "invalid" we get a memory item QRH drill required?
As I said above, I think the 60KIAs / Stall warn on/off, is somewhat a red herring in this accident. If the circumstances and/or crew get an airliner (as this crew did) to below 60KIAS I think it is probably game over, and no amount of training or certification can cater for it? You're better off (as has happened to a degree) stopping the crew getting below 60KIAS / 40AoA in the first place
NoD