The 37’s have gone through a number of improvements over the course of their operational history, none of which required a name change or a new type rating. The originals had low bypass engines, stubby wings and were relatively underpowered. I swear the wing engineering was a touch off, as the aircraft cruised at about a 3 or 4 degree pitch up. Cabin crew always felt like they were working on a slope. That all changed with the NG models with a new wing, entirely updated avionics and bigger hi bypass engines. All of this accomplished without a real name (737 NG) change or requirement for a new type rating for pilots. The MAX is the 3rd iteration of the venerated 73s that have possessed a top safety rating for 20+ years.
...Just to give a bit more historical perspective.
Thanks - but I just think they went too far on the Max and over-engined the small airframe.