GY, The F-16 deep stall was a result of its pitching moment characteristics in the stall, nothing more, nothing less. Not necessarily relevant to its unstalled characteristics which happened to be unstable by design while subsonic (and stable while supersonic). All different parts of the aircraft's flight regime.
To my mind once you get your airliner well away from the immediate area of the of the C
Lmax point on the high angle of attack side, you are beginning to get into an area of untested aircraft performance where anything can happen. You may as well define this as deep stall, because at that point, you are the test pilot. It is too risky for the airframe manufacturers to map this area. AF447 may or may not have been 'locked' in its stall but at 61 degrees AOA that is a deep stall in anyone's book. Even with positive pitching moment, it would take some time to rotate the aircraft to align with the airflow, and it would be very easy of overshoot into a negative angle of attack stall.
I went to some effort to obtain the PDF file I attached to this post
http://www.pprune.org/6509546-post1873.html . Do give it a read. The post stall characteristics of the airfoils tested were rather surprising to me.
