Big Pistons Forever,
The proposals (§) don't suggest a reduction in MCAS trim rate. The system's ability to trim the horiz stab still uses the higher rate, but limited to one application of xx deg, thus in normal operation it should to provide sufficient aerodynamic effect to meet certification requirements.
The changes appear to involve higher system reliability - MCAS / AoA should not fail so often (how and why is in the small print), and if there is a MCAS / AoA failure, detection and inhibiting the trim output is improved so that the trim cannot offset by more than the pilot is capable of recovering from.
The stab trim runaway situation remains, as it does for pre Max 737s; detection, inhibit, and recovery still depend on pilot intervention, although there could be a small numerical argument from re-routing trim wiring.
Will a single trim application per AoA increase will be sufficient?
If the same aero effect from a single application as previous - trim rate and duration, then yes
If not, then flight test judgement and cert interpretation, but some trim would be better than none of the basic aircraft.
Then the debate would again be changed from a hard numerical system safety requirement (10^ - x) to a subjective interpretation of a requirement - slope of the trim curve in rarely encountered situations with minor stability effect which pilots can control, and for which there are certification precedents.
§
https://www.faa.gov/news/media/attac...ummary-v-1.pdf