'This feature is pretty much covered by long-established procedures already. '
Well it obviously isn't or they wouldn't have crashed.
Boeing claim the runaway trim procedure deals with the issue, however runaway trim presents as just that, the trim motoring all the way to the stops, MCAS is an intermittent nose down trim that the pilots may think they've countered with the standard actions because it stops and they don't know about MCAS. If you've got more than one thing going wrong, and they did because one pilot's control was shaking to indicate approach to the stall, and their airspeed indications were mismatched, the trim occasionally motoring nose down and then stopping may not register as important until it's too late.
Biting the hand that feeds IT
