The difficulties that beset the crew of both the accident aircraft were the result of inadequate knowledge and awareness being imparted to the crew. This state of affairs resulted from the OEM complying with the constraints that were imposed by the airline customers, that additional training would come at a cost. Not doing the training or awareness related to the design changes came with its own painful cost to all concerned. The comprehension of the dynamics at play are now known, and that provides the basis of awareness training to mitigate the risks that exist in the aircraft design. The MCAS needs design change, however the risk exposed by the second accident is that the limitation of the manual trim necessitates dedicated awareness training for the crew on that aspect irrespective of the MCAS design change.
It is apparent that it was not considered that MCAS would fail in the way it did. Therefore, any simulation training prior to the accidents would not have included an MCAS runaway due to a bad AOA input as it was seen as a benign addition to STS.
The fix will almost certainly remove the single point of failure and prevent repeated large nose down trim events. So simulation training now for an event that is now not possible with MCAS would not provide any training value. What would provide training value is manual flight with electric trim switched off using the manual trim wheel - and that is something that applies to every 737 flying and should have been part of standard training. If that had been the case the 737NG pilots transferring to the Max would have already had the training required and this thread may not have existed..