Regarding the simulators: It's not so much as how to handle the very deep stall, that is to be avoided anyway and hard to recover.
Deep stalls are hard to get data because you can't do it in a real airplane to get data for the simulator.
The approach of the stall and the begin of the stall can be simulated adequately i believe. In this is case it probably is about teaching the technique i believe.
What i personally don't understand is why Airbus don't have the AOA gauge pop up at high levels when the AOA get's high. It's called Backup Speed Scale (BUSS) but basically it shows the Angle of Attack.
There is a video of the BUSS here:
So if the crew recognize the unreliable airspeed and switch off i believe two ADR they get this AOA indicator. Having it appear when the AOA is excessive would be great i believe. Should not replace the Speed Tape in that case though. Oh well i shouldn't start a discussion here there have been many threads on this forum about that incident. You could dig in those threads as well but those are many posts.
Also you will be aware that the type of probe that encountered the icing problem was changed/replaced i believe.