This is my understanding too, though Boeing hasn't really come out and said it definitively. Specifically:

> MCAS was devised to fulfill an airworthiness certification condition in 14 CFR 25.173 and 14 CFR 25.175. In high angle-of-attack (AoA) flight configuration, it is required that stick force/g (the stick force necessary to produce (hold) an incremental normal acceleration of 1g) and stick movement/g (ditto mutatis mutandis) must increase (or at least not decrease) with an increase in AoA (thanks to Clive Leyman for this formulation). I understand that in flight test, in which “wind-up turns” were conducted (a turn with increasing angle of bank; an increasing angle of bank means ceteris paribus increasing AoA), this condition was not fulfilled.

-- https://abnormaldistribution.org/index.php/2019/04/30/ieee-s...

@throwaway201103: “You're mostly right, but it wasn't just to make it handle like the previous versions, it was to satisfy FAA certification rules on how it handled.”

And also to stop the plane dropping out of the sky!