This very detailed post has an overview of the many design failures Boeing made on the Boeing 737 MAX.
Some very important ones:
1. Change the function the of the stab trim cutout swiches. As a result for the MAX electric trim is always disabled, while on the NG the autopilot stab trim could be disabled, while electric trim (via yoke) remains available
2. No mentioning at all about MCAS in the FCOM
3. Using a single AOA sensor as input for MCAS
4. No alert in cockpit about AOA disagreement nor information on the angle of attack value of both sensors.
Many more failures :
https://feitoffake.wordpress.com/201...oeing-737-max/