Regardless of the name change they are still grounded. Given all the scrutiny, when they finally do fly again they will likely be one of safest planes in the sky.
On what basis? They're trying to fix a fundamental aerodynamic design failure with a software patch. The entire physical design if the airplane is flawed, and they arent rebuilding the entire fleet, just pushing another software patch.
General Dynamics never claimed the F-16 was just a slightly modified Cessna in order to avoid having to retrain pilots and have it safety tested, however.
As I understand it, the 737 itself is not flawed, but when you add huge new engines that need to be much further forward just so they don't hit the ground, that's what makes it unstable.
The whole problem was that they were trying to pass off an airplane that now has very different handling characteristics as a 737, in order to avoid retraining and proper safety testing.
I did not read anything about investigating everything from scratch, there is a possibility that the bigger engines could affect the wings, or other subsystem and because they were rushing they did not test all the systems or downplayed the possible issues.
Adding to my doubts is the fact that all the incentives is to get back in business as fast as possible and safety is just a bump that Boeign needs to get around or over it as soon as possible.
Last big issue is the credibility of FAA, you had the first airplane crash and nothing was done, second airplane crashes and FAA again does nothing until it is basically forced to ground the plane. Without the pressure from the other countries the MAX would still fly today with all the issues and the pilots and airline would have got all the blame
In the lighter end of GA there are plenty of aircraft which have gone from having initially poor safety records to having some fo the best in the fleet.
The Mitsubishi MU2 is a good example, it had some interesting control quirks due to having a tiny wing for its weight. After a number of reviews a training package was designed which almost completely solved its safety problems.
The Cirrus SR22 was also in a similar category, despite having a whole-frame parachute. Their problems were solved by insurance companies demanding more training and their owners group pushing the mantra "if in doubt, pull the chute".
I'm sure there are better examples from the commercial air transport end of the scale but I knew those from the top of my head.