MFS,
Our views diverge; possible via my supposition of ‘elected not to disable the trim’, and similarly your ‘disabled the stab trim had they decided to’, which both involve hindsight and without knowledge of crew thoughts.
The issue is that there was no alerting indication that MACS trim was malfunctioning, thus the failure depended on crew deduction via the feel of the aircraft / control system, a situation which also included a ‘feel diff pressure” alert.
The certification point about immediate recovery is based on an obvious indication of malfunction (AP runaway) and thus instinctive action. Furthermore, after the recovery the crew have a normal aircraft to fly.
Whereas a MACS trim malfunction is insidious, intermittent, and accumulative unless corrected; it is a continuing failure affecting the control of the aircraft exacerbated over time.
It is this situation which might warrant ‘automatic correction’, even if only to disable the MACS with AoA failure.