Superman has his problems as a character to be translated to the movies, and truthfully I kind of blame the way Hollywood script writers work. It seems like when it comes to super heroes they get fixated on origin stories and the like, and that's a problem when your dealing with an iconic character like Superman since everyone knows what's supposed to happen, yet directors always want to put their spin on things and want to make things a bit differant. What's more, the coolest elements of Superman is when you have him doing cool stuff as an established hero, not as some dexter out in Kansas being a klutz. Even "Smallville" was smart enough to realize they had to move well beyond that.
I also think that there is an issue with the fact that people don't "get" Superman. Oddly I think the best analysis of the character game from believe it or not a satirical crossover with "Gen 13". Hollywood somehow wants to make Superman fashionable, and really I don't think that's possible because as Gen-13 pointed out, he's never really been fashionable to begin with. What keeps the character going, to the point of being an icon, and one of the must recognizable characters in the world? Quite simply Superman is reliable, he's a rock that you can always rely on, Superman shows up and you know that no matter how bad it seems, it will be okay in the end. Truthfully I think the problem with most versions of the character is that they almost revel in trying to humanize him, or see him get his butt kicked, sometimes in stupid ways "I never liked the big blue boyscout anyway" is a frequent comment. This however seems to miss the point of the character and why it has endured all these years.
It doesn't surprise me that there are major problems with a Superman script, because honestly Christopher Nolan is all wrong for the material. His style is pretty grim and gritty, and that can work with Batman. I mean part of the point of Batman is to be a humanized super hero. With Superman though, that's not the case, he's supposed to be
upbeat and four color, angst is not really part of what he's about, he can shrug off any adversity even when challenged and will always keep that "can do" attitude. On the few occasions where this is changed he has shrugged it off fairly quickly.
See, the thing is that all of these dark heroes, and angst-filled stories come accross as being profound because they are supposed to be a contrast to the style of super heroism that Superman represents. You start turning Superman into a dark, or very human hero, and then you have nothing as a counterpoint. I like my dark heroes, but at the same time when it gets to the point where EVERY hero is dark, well they lose something.
It's sort of like the point Moviebob was making about Michael Bay being wrong for the material he was doing in "Transformers", Christopher Nolan is a great guy to have around for doing Batman, but he should be kept away from Superman by any means nessicary. Sadly, I don't think Hollywood truely realizes that there are differant kinds of super heroes, and differant styles of storytelling even within shared universes.
The last thing we need is "superman gets depressed, and wallows in self doubt" to be a plot point, nor should a story involving Superman have an ambigious "he won, or did he?" type ending. Superman is not gritty, when it's over he's supposed to put the American flag back up, pose dramatically, and let you know that the good guys flat out won, and everything is not only okay now, but will be forever because we've got bloody Superman.