Good article but some factual inaccuracies.
Let’s review what the MCAS does: It pushes the nose of the plane down when the system thinks the plane might exceed its angle-of-attack limits; it does so to avoid an aerodynamic stall. Boeing put MCAS into the 737 Max because the larger engines and their placement make a stall more likely in a 737 Max than in previous 737 models.
When MCAS senses that the angle of attack is too high, it commands the aircraft’s trim system (the system that makes the plane go up or down) to lower the nose. It also does something else: It pushes the pilot’s control columns (the things the pilots pull or push on to raise or lower the aircraft’s nose) downward.
The system isn't designed around stall prevention or indeed AOA limits. It is there because the lift generated by the relocated engines reduces static stability when at relatively high AOAs. In other words, without MCAS the pull-back-on-stick force required from a pilot to raise the nose reduces as you increase AOA; this is an unsatisfactory feature as far as certification is concerned and contrary to the effect that one normally experiences when pitching-up. Boeing got around this by developing MCAS which intentionally puts the stabilator in a nose down out-of-trim position when it thinks you are at a high AOA. (Have a go when flying sometime, maintain straight and level and then trim nose down - you'll have to apply increasing amounts of back pressure to maintain attitude as you add nose down trim
The problem is the result of an aerodynamic issue which is 'fixed' by intentionally taking the aircraft out of trim. An unfortunate side-effect is that MCAS is a bit of a simple soul and it will continue to want to trim nose down as long as it is getting high AOA data. Somewhere along the line, the nose-down trim on the stabilator will require a force greater than the pilot can apply in trying to pull the stick back. Indeed, there is probably a point whereby the effect of full elevator (if you could ever get there) would not be enough to counter nose down stabilator.
From a safety manager's perspective, the development and introduction of MCAS will in the future provide excellent case studies in how NOT to design an aircraft system.