People blow things out of proportion. I was on one site yesterday where somebody listed it among the worst superhero adaptations of all time. That's utter bullsh**. I don't care if you hated MOS, there's no way it's in the same company as some of the crap we've gotten over the years like Catwoman, Fantastic Four, Green Hornet and The Spirit.
I guess is with Superman, people just have this preconceived idea of how they story SHOULD be told, how the character SHOULD act, etc. What they don't take into account is that Superman has been rebooted multiple times in the comics, and some of the changes have been drastic. You also have to consider that the writer and the director of a film adaptation are going to want to try and do something at least somewhat fresh and original, otherwise, what's the point? No one wants a carbon copy of an older film only with modern special effects.