Superman is practically a god, so to me what I would find interesting is a plot where Superman is truly, honestly pushed to or beyond his limits. Hopefully in a combination of ways. Watching him get into a huge physical fight with someone who can go toe-to-toe with him (I'm not endorsing the storyline he's associated with, but Doomsday?) can be fun, but to me that's more icing than it is cake.
But doesn't giving him a villain as powerful as him undermine the point that he's supposed to Super?
In theory you present him with someone who should be his equal, or perhaps even (apparently) better, and he proves he truly is super by beating him in the end anyway.
The only thing I see about Superman is that he's really powerful without much of personality or anything else.
Agreed. This is why Superman stories have yet to truly capture me. I think that may be why I appreciated Singer's choice to play up the father/son relationships because it gives him a real heart and soul. Having issues with my own father(s), I swallowed it hook, line, and sinker, and it made me care more deeply for him.
Now, obviously that didn't work well enough for everybody, so that's clearly not what they'll go for again in the reboot.
I'm struggling to see what else they can do to make Superman more than just "goodie-two-shoes with tons of power".
And the only thing for me that makes Superman so powerful is the ill-defined nature of his powers. He's super strong, how strong? I don't know, just really, really strong. The same with his speed, invulnerability, and others.
The answer is, apparently, "as much as need needs to be." I doubt we ever see it quantified.
Why should I care about superhero whose hero-villain plot is the most obvious and inorganic of all?
That's the real trick.