Personally, I thought Singer's radically different tone and visual style, as well as the poetic, reflective nature of the story, were MORE than enough to make SR feel like it's own thing.
Don't get me wrong; it definitely felt like its own thing, and it was a boring
thing. It was just too subdued and languid and lacking in any real interest. I tend to imagine it's because Singer was just doing a fanboy homage, that if he'd really been fired up to create something original, he would've done better. Maybe I'm wrong. Maybe he's simply the wrong person to do Superman. Maybe it would've been languid and solemn and lacking in fun no matter what he did.
But I have to wonder -- could Singer, the man who created such a compelling Magneto, have given us a more interesting Luthor if he hadn't been emulating the Donner movies' lame version of the character, but had instead based it on the modern comics' corporate magnate or come up with his own original archvillain type? Would he have come up with a more satisfying Clark-Lois dynamic if he hadn't seen it as a continuation of their love affair in Superman 2
? And would it have been easier to accept the new cast in their roles if the film hadn't been encouraging us to pretend they were the same people previously played by Reeve, Kidder, Hackman, et al.? All those things diminished the film for me. Maybe a Singer Superman film still wouldn't have been very good without them, but they were part of the problem.