Undisclosed changes in switch function
1 As I gather, on previous versions one cutoff switch blocked autopilot trim while allowing electric trim to continue working. The other switch cut off power to the trim motor from all sources. With the advent of the MAX, you now have to give up electric trim to block MCAS.
We do not yet know how effective electric trim is when the stick shaker is operating. Possibly the usual light touch on the switch may not be enough to sustain electric contact with stick shaker on. Have to wait for the report on that unless somebody finds time to research it on a sim.
2 The underfloor control column switch blocks autopilot trim, but not MCAS
Neither seems to have been disclosed.
We can talk about crew training, but the new MAX curriculum seems short on vital facts.