As I understand it the aircraft (if not the pilots) knew the AOA was too high. So perhaps changing the audible warning to announce the AOA would be benificial.
At the very least change it so that the warning isn't the same pre and post stall.
It seems they never realised they were fully stalled so can you really blame them for they way they responded?
The other possibility is that one or more did realise they were stalled but assumed the PF realised it and had tried to get the nose down. There is a lot less discussion of the situation than I expected.