Firstly I believe Boeing should refrain from any mention of what training might be required - my understanding is training requirements are the domain of the regulators, not Boeing. So just put forward your proposed fix and debate the outcome.
Secondly, I think every regulator should get hard evidence that the MAX meets every requirement "possible" that MCAS was developed for to meet certification - I simply can not understand how the new "handicapped" MCAS, can now keep the MAX within the certification requirements.
Thirdly every change made to the MAX must be justified as to why it was made, and exactly why no extra training was or will need to be give - this is not limited to MCAS.
Another step should be a list of all persons that were involved in discussions and decisions over the MCAS on the MAX and access to privately interview them - I doubt this will ever happen as I expect there is more to hide.