Here's the thing about Superman Returns:
It's not THAT bad.
I wouldn't even call it "bad", it's just... misguided, really.
Instead of reinventing Superman for a new generation, here's a film which decides to pay homage to those old Christopher Reeve movies, the only Superman movies we've ever seen. Was that really necessary? No. That was a bad idea to begin with: not original, not ground-breaking, not different.
As a slick retread and as a sort-of sequel to Superman II, however, it just about works.
You've got Kevin Spacey taking on Gene Hackman's Lex Luthor role and doing a really good job, though he's only a tad more threatening than Hackman was back in the day. The film looks good, the classic Superman theme is still there, the action sequences (all TWO of them), as rare and far between as they may be, are really well done and Bryan Singer's direction is slick and stylish. That said, there's a serious problem when it comes to pace, the story is flawed and mostly unexciting and, sadly, Brandon Routh, as decent of an actor as he may be, is no Superman.
Routh is honestly way too young for the role and just doesn't have the physique to pull it off. Had they cast Henry Cavill back then, that would have made sense. Even as Clark Kent, a role he's much more convincing at playing than Superman, Routh feels like a kid pretending to be Clark Kent. Also, I don't think that giving Superman a creepy-ass stare helps to make him relatable and likeable, especially when he's spying on his ex and sneaking into her kid's bedroom. Really, having the hero disappear for five years on a selfish-ass nonsense mission only to come back empty-handed and expecting everyone to be ok with it was a mistake. This only helps to make Superman look even more childish and naive than he already does.
Now don't get wrong, Christopher Reeve's Superman did his share of stupid things (see Superman II) but you expect better from this movie. Kate Bosworth's Lois Lane didn't bother me as much as she did most people, that said, she also looked too young and was overall kinda bland. James Marsden is in this movie, hence why Cyclops got shamefully tossed aside in X-Men: The Last Stand, and his character actually comes off as more heroic than Superman himself somehow.
The plot sees Lex Luthor inherit a yacht and tons of dough from some older lady he had been taking advantage of before coming up with a real-estate scheme involving kryptonite and crystals. This hardly feels like a worthwhile plan which'll make sense in the long run, especially since it all rests on him and three henchmen and, at any moment, the army could just bomb his island with him on it, Superman or no Superman. It just feels like the whole kryptonite island thing is building up to something bigger and more substantial, but it never does. Instead, we have to sit there and wait for the obvious to happen before pretending that Superman's dead for 5 minutes when there's no way that could ever be the case.
This movie needed a different approach altogether with a more substantial plot because, as it stands, even Superman IV was far more involving. In Superman Returns, you can tell there's a good movie in there somewhere but so much of it is so bland, the lead is so miscast and it's so uneven that it leaves you feeling a bit empty.
Overall, I don't hate Superman Returns. A third of it is actually good, the rest is just either slightly dull or a bit misled. You've got some cool action sequences in there with some decent effects, some solid performances, some good ideas... it's an ok (and good-looking) movie just not a great or particularly exciting Superman movie.
A bland, if watchable, effort.