PJ2-
I think the one thing that I would like to have seen done different on the design side is the installation of AoA guages.
The rest is on the training side, to include how to use the AoA guages. This crew never knew they stalled. There have been plenty of examples of other crews stalling without knowing it, and those included highly experienced pilots with aerobatic and military backgrounds. The factors that led to them not knowing are several and I know they are known to you.
Pilots are also not trained to know the automation well enough to make predictions on what it will do next, or should do next. The training in the hq in the high altitude regime is scant, and simulators do a poor job of replicating it all. Similarly, training in the hq in degraded modes, particularly at various q-factors is missing.