[Capt. Tom]

The redesign of the 737-800 Max resulted in an aircraft that was unstable in pitch around the lateral axis when flown at high angles of attack and under conditions of high thrust. Rather than address the underlying aeronautical design flaws, and risk certification as a 737 variant, a decision was made to fix the problem with a "software kludge" the MCAS system.

Since the larger more powerful engines were used and relocated, and affected the trim on takeoff, you would have to make some physical alterations to the wings and tail of the plane to offset that engine change.

Using MCAS software to accomplish this was the less expensive way of correcting this.

What I don't like is not having the second external flight plane indicator made mandatory and being specific in what to do if you get two radically different readings - Tom

[TexasGator]

“Since the larger more powerful engines were used and relocated, and affected the trim on takeoff, you would have to make some physical alterations to the wings and tail of the plane to offset that engine change.
Using MCAS software to accomplish this was the less expensive way of correcting this.”

WRONG. THE MCAS is totally disabled from actuation during take off.