jcj - I think you're reading a different meaning into my words than I intended. This problem is a new one that seems to have arisen with a recent modification to the AoA vanes, intending to solve the issue of the icing up of one vane that occurred on AF447. It appears that the fix passed certification and began to be implemented, but the certification tests were not sufficient to catch this new issue (in other words the fix seems to have made the problem worse - with all three vanes freezing in certain conditions).
As with the Thales AA pitot tube design, this incident shows that the certification process needs to be revised based on the evidence presented. EASA and Airbus seem to have been pretty quick in getting the EAD and workaround published once the problem was known.