gums, et al,
We wait for information about the modifications.
A likely scenario is a monitored dual system using the existing FCCs - two required for dispatch. If MCAS shuts down in flight, then providing the stability shortfall is minor, the flight could be continued.
However, more serious stability discrepancies / stall characteristics, would either require a new software architecture using three sensors, or as rumoured a third ‘synthetic’ source of AoA which would enable continued flight or diversion.
Manual flight training would be required to experience the stability differences with MCAS unavailable.
For the trim runaway aspect, stick cutouts, trim alerting, and crew procedure should be sufficient, but this could depend on any differences between the MAX and NG. Training would be essential for quick identification and action, likely stick force, and or ease of trim opertation.
The high workload / distraction problems at or after takeoff due to multiple alerts could be tolerated, but again with training; although the stick shake implications - stall or not stalled, could add a few changes.