Ironically, I believe that your information is also inaccurate. MCAS is required
in order to meet federal airworthiness requirements. Without it, in certain flight conditions the back-pressure on the control yoke gets less as the yoke is pulled further back. It's like over-steer in a car, and is simply not allowed. Yes, the plane is dynamically stable; if you leave the yoke in one position it won't pitch up even more. However, the forces must be corrected somehow, regardless of type rating concerns.
"The 737 MAX was a bit too easy to pull into a stall when flying with high AoA and making abrupt maneuvers. The larger engines for the MAX hung further forward from the wing, added a destabilizing aerodynamic area ahead of the center of gravity, destabilizing the pitch moment curve at high AoA.
Boeing and the certification authority, FAA, decided added margins was called for. Boeing added a pitch augmentation at high AoA called Maneuvering Characteristics Augmentation System, MCAS.
The aircraft should trim nose down to increase the stick force needed once it passed into the light grey area where the base aircraft had a region of less stability. Before the augmentation, the pilot felt if the aircraft wanted to fly into the stall, it got easier to increase the AoA after 12°AoA. With the augmentation the felt extra force was the same for the first and last part of the curve before the maximum lift was achieved at stall (and stall warning kicked in)." [0]
The manner of the fix (MCAS transparently pushing the nose down) was designed to avoid pilot retraining and thus keep the same type rating.
Edit: The fact that the 737-Max needs a handling tweak is not a failure. Modern planes have all kinds of these tweaks, whether aerodynamic (such as strakes), mechanical (stick shakers) or enabled in software. As the cited article continues: "So far so good. It's common an aircraft’s flight control system has fixes to stability margin changes in different parts of the flight envelope." The problem is that Boeing had a pretty severe collapse of its systems engineering regime.
"The implementation for the 737 MAX had two problems, however:
- The fault checking of the triggering AoA signal was not rigorous enough. This problem has been discussed a lot. No need to add anything.
- The judgment the pilots would identify a problem with the augmentation as a trim runaway and shut the trim off was wrong. Why the pilots didn’t see MCAS rouge actions as a trim runaway is poorly understood."
(The article was published in February. Since then lots of information has come to light about how MCAS determinedly fought correction, and the huge mental and physical loads imposed on the pilots.)
Edit 2: FAA regulation mandating increasing elevator forces for all transport aircraft: FAR §25.253 High-speed characteristics, (a) Speed increase and recovery characteristics, (3):
With the airplane trimmed at any speed up to VMO/MMO [maximum operating airspeed], there must be no reversal of the response to control input about any axis at any speed up to VDF/MDF [maximum airspeed demonstrated in testing]. Any tendency to pitch, roll, or yaw must be mild and readily controllable, using normal piloting techniques. When the airplane is trimmed at VMO/MMO, the slope of the elevator control force versus speed curve need not be stable at speeds greater than VFC/MFC [maximum control airspeed], but there must be a push force at all speeds up to VDF/MDF and there must be no sudden or excessive reduction of elevator control force as VDF/MDF is reached. [1]
[0] https://leehamnews.com/2019/02/08/bjorns-corner-pitch-stabil...
[1] https://www.ecfr.gov/cgi-bin/text-idx?node=14:1.0.1.3.11#se1...