It is a minor change. There is nothing inherently wrong with adjusting the flight controls so one airplane flies like another. In fact, engineers try to do it, as it reduces both costs and accidents. (There have been many aircraft accidents where the pilot did the right thing for airplane X, but unfortunately was flying airplane Y. These happen even when the pilot is experienced and properly trained to fly Y.)

> Software development for aviation is pretty good, that's not where the issue lies here.

MCAS is a software system, and the rules programmed into it had human factors mistakes in it.

You might want to read Aviation Week, 19-Aug, for more detailed information.