I agree, it would be good. But it's a big, big step...the FAA would have to mandate this, adjust FAR 61, and educate the CFI population.

Then primary trainers would all need AoA gauges...along with their ADS-B out.

None of the big flight schools are going to do it unless it's mandated...it would drive their costs above their competitors in the short term.

I'm not sure I can envision a practical roadmap to get there...AOPA and the FAA (and maybe the NBAA) would have to agree, and the RAA would fight it tooth-and-nail since it would increase the cost of fresh seat-meat ever so slightly, and would impact their training programs.