It was so poorly designed that the end result won't fly without a computer program to make extreme flight control inputs to keep it from *increasing AOA too quickly with too little backpressure.
I completely disagree with this sort of doom and gloom assessment.
Winding in forward trim is not "extreme flight control input".
MCAS only acts (by design) in a part of the flight envelope that is rarely entered, not even close most of the time.
The issue was ONE vane sent erroneous data and there was no second vane input to compare it to and stop MCAS activating. That is the actual issue.