Roulishollandais: specificity of deepstall which has PERHAPS been the case in AF447.
Saying that shows that you are honest and open-minded.
In fact I believe it was a perfect example of deep stall. Stable, with only roll excursions. The angle of attack at a very high value, and a stable (awful) rate of descent. To "break" this stable descent, you need flight control efficiency to decrease the angle of attack (with a full "up" THS (or PHR fot the french) was the elevator sufficiently powerful?) and you need to use engine's secondary action (reducing completely will help to decrease the angle of attock)...
But every plane has its idiosyncrasies, and this had never been tried on the A330. I remember, long ago, in Bretigny (flight test center at the time) a French Navy Crusader being tested after two losses following unrecoverable spins. The test pilot used full reheat (post-combustion) to manage decreasing the angle of attack and getting out of the spin. I worked a lot with him later on, and of course, if he had been in the A330...But such pilots are scarce in the airlines nowadays.