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.
I'll post the usual counterpoint: this isn't a new. The F-16 for instance is also famously unstable, and cannot be flown without computer assistance.
https://en.wikipedia.org/wiki/General_Dynamics_F-16_Fighting...
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.