Is the "dual input" automatic callout now implemented in all fbw airbus? I once read a very interesting incident report about an in flight incident with a lufthansa A340 in US airspace where dual input lead to a very fast pitch oscilation generating -1.2 and plus 2g in less than a second leading to some injured cabin crew. It was noted in that report that there was no dual input callout since that wasn't implemented in the A340 at that time so both pilots were unaware that they had added up inputs.
Another incident where the priority button probably saved the day was the lufty a320 wich had the left stick roll channel crosswired so that the PICs inputs worsened the effect of a gust after lift off instead of lessen it, a very fast FO (who was pnf) switched priority and took over (wing to ground clearance was as low as 30cm).