Yo gums, #804 You invite comment.
Your ‘The plane should require more force to reach stall and not less’, has the essentials. Pedantically, the stick force should increase with decreasing speed, similarly with nose up manoeuvre. Also, considering effects of increasing thrust.
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It appears that the 737 Max, whilst retaining positive stick force stability throughout the flight envelope, does not exhibit sufficient to satisfy certification requirements. This ‘stability’ as sensed by the pilot (stick force) is ‘artificially’ increased by applying trim - MCAS. Because trim is so effective in the 737, the amount required is relatively small.
The small part of the fight envelope and flight conditions requiring enhancement suggest that flight without the MCAS trim would not be overly demanding; there is no step change between requiring trim (certification) and normal operation. However, the 737 in general appears very sensitive to nose up pitch change due to power increase - GA low speed, thus there is added concern.
Assuming that modification prevents any significant trim deviation due to system / sensor malfunction - it must, then all the crew need to know from training are the principles of MCAS (like STS), awareness of when MCAS is not available, and thus the need for careful handling. The points above suggest that the critical manoeuvre is GA - simulator training debatable.
The proposed mod does not provide a clear alert that MCAS is unavailable. MCAS inhibition has to be deduced from other indications; a minor point which might be forgotten during the surprise of a GA.
This would also be a basis for discussion by the certification team, as should the potential misleading indications from AoA display with disagreement.
The duration of the re-certification (flights / hours), as speculation, could indicate that other aspects have to be considered based on the accident findings - e.g. recovery from trim runaway. Are the assumptions that pilot identification and intervention in 737 NG, et al, still valid, and can these be assumed for the 737 MAX (grandfathers), given that the MAX appears to differ from other 737s due to the need for MCAS.
Perhaps even more surprises as long as there is no publication (or leak) of exactly what caused an erroneous value of AoA. How do you fix something what cannot be identified, nor repeated (software glitch, chaffed cable); you might be able to prevent a hazardous outcome (mod), but how sure - certification - public perception, lawyers; this could get interesting.