I recall when Frontier Airlines went to two man crew on the 737 (circa late '70s), some Western Airlines crew tussled with a Frontier crew on a shared crew shuttle bus, in Denver, over this issue. I agree that having three crew seems safer. However, my observation is that overcompetence is as dangerous as incompetence, just more insidious.
Frontier Engineering realized one benefit of going to two crew...cabin altitude squawks went away!!
Went into Deerlake, New Foundland, in a snowstorm, on an Eastern Provincial 737...that was exciting!
Putt