While I have no personal experience with the Boeing 737 I do have a wealth of experience with tactical aircraft and missiles and I have a degree in aerospace engineering. I recall seeing that Boeing has a backlog of 4000 737 planes to deliver, but was under increasing pressure from Airbus because there was not a large stretch version of the 737 to compete with the A320 (or it could be the A350, sorry). Boeing rushed the 737 Max into production out of fear of losing market share.
The original 737 had relatively small engines and sat low to the runway. The 737 Max has very large engines and sits significantly higher. More importantly, the 737 Max, because of the very large engines develops Lift off the engine nacelles. This fact moves the center of lift for the 737 Max forward. The shift forward creates a new static stability case for the phugoid mode and the aircraft is no longer statically stable in the same way that it was. The correct fix would be to move the wing back, perhaps inches, perhaps feet. Moving the wing back would require new jigs for the production process, another delay Boeing was unwilling to accept. Instead, Boeing went with a software kluge that didn’t work and cost 346 lives.
The bottom line is still, profits are more important than people’s lives. Keep in mind that Boeing was fearful of eating into a 4000 airplane backlog. Now Boeing is eating away at its credibility.