It might work perfectly for all sensible flight regions, but there's always that 1 untested case where a fault in the logic appears
Which is why it is so critical that original and modification design having any direct impact on piloting must be assessed rigorously by experienced flight test folks. I am sure that this occurred throughout at Airbus .. just tragic that this outlier caught everyone out ...
But if you "gestalt" what went on over a period of about two minutes, what teases out of the background noise is the clear potential for assessing what had happened and what was happening.
One of the underlying problems - here and in general - is mental overload.
I'm sure we have all experienced the sort of problem.
I recall one such very clearly. An experienced 727 crew, but quite a few years' worth of being rusty on the Type, requalifying on the bird over at DFW. First sim session, engine failure, F/E missed this and that, with the result that I ended up with hydraulics out as well. Hadn't had any flying at all for the previous couple of years and was working well and truly above my comfort zone level. I quite clearly can remember seeing the bank continue to increase and fixating on control input to correct. The other driver, being relatively relaxed in the other seat .. put two and two together quickly and pulled back the other pod thottle, giving us time to sort out the rear panel oversight. Very sobering experience and resulted in some soul searching that night over a beer or ten.
Regardless of what we may think of AF447 overall, one really needs to maintain a degree of empathy for what must have been an extremely confusing and confronting situation for the two guys in the hot seats. Just a pity one of them wasn't sitting back relaxed and able to think a little about what might have been going on at the time .. rather than both getting too involved.
Philosophically, from a command management and SOP point of view, not all that different, for example, to the Eastern trimotor Everglades mishap of many years ago ? Trivial problem, breakdown in cockpit discipline, and the bird is lost ..
It's very easy for us greybeards to opine that we wouldn't have been caught out on the day ... but, change the circumstances a little, here and there, and the situation might have been an eye-opener for us in a similar manner .. ?