I did our Airlines high altitude stall routine on both the B737-400, and the 320 series. . As a former light aircraft pilot I would say that one of the most significant issues, at least to me, is pilot stall perception. Civilian pilots who did their primary training in general aviation aircraft, Piper or Cessna or similar, are used to a definite stall break that signifies the full stall. It is easily observable and definite. I found this to be even more pronounced with aerobatic aircraft.
The B-737 simulator would stay in a stalled state with almost no break with an aft C.G. It required a forceful push and re-trim to get the nose down below the horizon and recover from the stall. The stick shaker and stall warning were going the whole time. It is easy to lose 3000 feet or more starting from 37,000. There is very little excess thrust available.
This situation is not recognizable as a stall with the prior training civilian pilots have had. Yes the stall warning devices are active and working but unless the pilot forcefully puts the nose down and lowers the angle of attack the stalled condition continues. Most light aircraft don't behave this way, not the trainers at least.
This is simply my own perception but I have a lot of time in the B73 and A320 and they both have a very wide cg envelope. The auto-pilot will also mask the problem as it re-trims to maintain altitude. You end up with the trim on the aft stop and an airplane that doesn't break the way a light airplane does in a stall.
FAR part 25.201(3) (d) says the following about transport category stalls.
3) As soon as the airplane is stalled, recover by normal recovery techniques.
(d) The airplane is considered stalled when the behavior of the airplane gives the pilot a clear and distinctive indication of an acceptable nature that the airplane is stalled. Acceptable indications of a stall, occurring either individually or in combination, are—
(1) A nose-down pitch that cannot be readily arrested;
(2) Buffeting, of a magnitude and severity that is a strong and effective deterrent to further speed reduction; or
(3) The pitch control reaches the aft stop and no further increase in pitch attitude occurs when the control is held full aft for a short time before recovery is initiated.
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25-84, 60 FR 30750, June 9, 1995; Amdt. 25-108, 67 FR 70827, Nov. 26, 2002]
While a nose down pitch that cannot readily be arrested, is one indication; but it is not a requirement. Buffeting and pitch control at the aft stop with no further increase in pitch attitude are also acceptable indications.
This is not something most former light aircraft pilots experience and we do not teach full stalls in the sim until the new regulations. The current sims may not produce the desired modeling anyway.
Here endith my limited knowledge of the issue.