Some good points, safetypee, and well put.
My personal experience combined with what we know about human performance factors suggests that the brain will ignore hearing in a crisis and therefore the audio "stall stall" is too subtle and might not be even noticed.
A visual warning on the PFD might work, but if the PFD is already confusing the pilot, then it might only cause more confusion. As a civilian pilot, I have never flown with an AoA gauge, so cannot comment. All the Cessnas, Pipers, Shorts, Dashs, and BAe146s that I flew previous to the Airbus have some sort of shaking felt through the controls as a stall is approached - either actual shaking of the horizontal stabiliser felt through the yoke, or an artificial stick shaker.
As a previous electronics engineer, it would seem to me a simple matter to make the Airbus side-stick vibrate in order to warn of an impending stall. A vibrating element such as the type used in mobile phones could be fitted into the side stick - in place of that oval panel on the top, and a small electronic driver circuit the size of a matchbox to convert the already present stall warning into pulsing the vibrating element on and off could be constructed for a few pounds. The wires feeding the vibrating element would route through the same channel in the side-stick as the wires to the PTT switch. So it would be a very simple retro fit.
Then, no matter how much the pilot's hearing had shut down, and no matter how confusing the PFD might be, the pulsed vibrating of the side-stick in their hand would warn of a stall, and should provide an instinctive un-stall reaction.
Some might say that I should not be thinking of modifying the aircraft, but this problem has killed people, so something should be done.