The idea of kryptonite goes beyond just mere tradition. The word itself has become apart of our lexicon. You hear the word used in pop songs, movies, and tv shows. You hear it used in sports. You hear it used figuratively, you hear it used literally. It's might not even be beyond your average joe to refer to something - either a weakness or a vice of his perhaps - as his "kryptonite". That's how engrained the concept has become in our everyday life. You have 75 years of history to thank for that.
I don't want to put Superman and Jesus on quite the same pedestal but Superman is about as close to an american born savior figure as there is. At the very least he's become head and shoulders the most mythologically profound. There are just certain inherent truths about the character that are so cemented in the minds of everyone that there's just no point in trying to erase them. Just like everyone knows that Jesus was a carpenter, everyone knows that Superman's weakness is kryptonite. It's that widely known.
So what? Why does that mean someone writing a Superman story is obligated to include Kryptonite? As I've demonstrated, there have been plenty of great Superman stories without Kryptonite in them at all and no one cared. If you don't include Kryptonite in a Superman movie (which, by the way, already happened with Man of Steel), in what way does that make the story less? In what way is the audience's appreciation of the film enhanced with the inclusion of Kryptonite, even if they find other ways to challenge the character without it?
You're right, I find Superman's struggle is most interesting at the emotional and spiritual level... not the physical. But physicality is also one of the defining aspects of Superman. His superhuman strength, his ability to fly... most likely these are the things that drew us all to the character as small children to begin with. And seeing him in such a physically weakened state - almost pitiful even - because of his exposure to kryptonite is something that clearly must have left a strong impression on our young minds or else the concept of it wouldn't have endured like it has. And not only that, but doesn't it also serve as something that helps ground the character a bit?
A big part of the concept endured because writers liked having an easy way of writing peril for Superman where they didn't have to think too hard.
And what's wrong with creating physical peril for Superman by having him go up against something that's powerful enough to hurt him? How does that not leave an impression? And why is Kryptonite better?
What leaves a bigger impression, Superman getting sick when someone pulls out a green rock that we all know can make Superman sick for vaguely defined reasons, or Superman coming up to an unknown figure and that person out of nowhere lays the smack down on the most powerful living being on the planet?
I think you'd be surprised at just how less interesting Superman becomes once you rob him of his achilles heel.
I fail to see how it makes him more interesting. You can accomplish everything Kryptonite accomplishes with more interesting things, with character, with moral dilemmas, with actual well thought out obstacles that Superman can't just punch his way through and can even kill him. Superman is not less interesting without Kryptonite. Superman is less interesting
with Kryptonite. I give a little shout for joy in every Superman story that Kryptonite doesn't make an appearance in because it is a destroyer of drama. My favorite thing about Man of Steel is that there was no Kryptonite.
I applaud a writer's efforts to try and tell an engaging Superman story without resorting to kryptonite because it means they're probably challenging Superman in other, more spiritually meaningful ways. But every single person that reads a Superman comic, or watches a Superman cartoon, or watches a Superman movie... in the back of their minds is implanted the idea that this guy would go down at any given moment if that shiny green rock were to somehow present itself. It's just an accepted truth at this point.
So what? Why does that mean we have to actually use it ever? Let them keep having it in the back of their minds. Not seeing Kryptonite won't ruin the story for them. There are tons of great Superman stories that are universally beloved that don't feature Kryptonite and no one cares.
What you're suggesting is that DC rewrite the mythology so that kryptonite doesn't exist. I'm saying that simply isn't possible. It's too late in that character's history for you to try and ask everyone to forget something so central to Superman's being.
It isn't rewriting the mythology. It's just choosing not to include Kryptonite in any of the movies. And it's not asking them to forget it, it's simply not using it. They can remember it all they like.
Tell me, what do you think the ramifications will be if the upcoming Superman movies never use Kryptonite? And don't say "it will be sacrilege." What will be the actual problems it will cause? How will it make the movies worse? How will it make people like the movies less?
If it's possible to make a Superman story without Kryptonite, then why not do it? Why would anyone be obligated to do it even if the story doesn't call for it?