Yeah, the point of losing Pa is not about him preventing a planet's destruction or even about the father having to die before the son can accomplish something.
It's meant to be the point where Clark learns that he can't save everyone and he isn't infallible. It's about why he has humility despite his godlike powers.
That's why pre-Byrne (who, god knows, is far from able to understand a character with humility), the death of one or both of his parents was always part of the Superman origin. It was the failure before the triumph.
i always hated this argument. so any adult with a living father isn't a real adult with humility? come on, that's just stupid. Clark could make the wrong choice between two people on the opposite sides of metropolis, or make a simple mistake.
mark waid wrote a great flash story where a villain is attacking a mall and there's a burning store. wally asks if anyone was in there, someone says no and wally says "i won't check then" and goes off to the fight. a few issues later he's sued by a woman who was in the store and ended up burned horribly and lost her legs. he learned humility because he made a simple understandable, but wrong, choice. the stranger who wasn't his father still had an impact.
and the original superboy story where the parents died involved time travel. hardly a grounding story where he learned humility.
and isn't it a little weird that the adult experienced superman lacked humility, by your logic, until now?