We're getting into too much detail I think... some who know very little about the Airbus (those who don't fly it), some who know a bit (those who do fly it).
First of all, AoA Failure ECAM messages are available, however, they are for heating failures. As alluded to above, detecting the AoA "failure" of it being frozen is difficult - it is giving a perfectly valid output. The only way of deducing the failure is to apply an algorithm to the AoA values and determine if they are "sensible" versus other values - but how do you now know if it is the AoA or the other (IAS?) value in error? AoA goes into the ADR (ADC equivalent) - and one would assume if the AoA value becomes invalid, or out of range, then that ADR will come off line.
If you try to apply a voting system then we have the ultimate quandry here - it seems 2 AoA values were almost identically in error, and the 3rd correct. Good job the logic did not outvote that one, which remained and gave the (correct) STALL warning.
Some drills do require pilot assessment - ASI discrepency for instance - to analyse and determine the faulty eqpt precisely because of the consequences of an "automated logic" getting it wrong.
As above, I still remain to see how the current design can lead to a credible accident scenario in normal ops. You cannot design an aircraft to prevent people having accidents when they choose to operate so far outside the "rules"... let us remember the purpose of the "test" - to check the AoA systems were acting correctly.
NoD