Eh, it's an ok scene. I just found it awkward and inconsistent, and out of character.
A knife is not kryptonite. You are missing the point entirely. The man is SURROUNDED by the element that literally poisons him. He touches it, it BURNS him, saps his strength, etc...
How anyone can call that lame is beyond me. Hard to believe? Cheesy? Sure. But actually lame? Eh, to each his own.
The movie went to some lengths to show why he was able to lift New Krypton in the first place. One, he soaked in a lot of solar radiation, and two, the Kryptonite was not seeded all the way throughout the continent. There was rock below it, shielding him from it's major effects until it continued to grow through as the continent grew in size.
Bunk. If that's supposed to be a "character moment", it's a poor attempt at one. Since there's never any doubt Alfred was backing Bruce, him saying he won't ever give up on him is kind of pointless. And Bruce's reaction the manor burning is just incredibly forced. You can't just "tie" something to something else if you haven't bothered to develop that something and something else. That's what Goyer tried to do. He (or Nolan, whoever's gem it was) figured "Hey, this will be a great character moment". But it's that "Now we'll have one character repeat something he said earlier in the film to drive home the trite lesson of the film" school of screenwriting. A la "No sacrifice, no victory" in TRANSFORMERS. Completely meaningless even when taken into context because there's been no exploration of the topic during the film. Now, had BEGINS had some exploration about Bruce's abandonment issues and how that related to what he did psychologically...
But it didn't.
Lost on the filmmakers apparently was the fact that Bruce Wayne spent half the story/movie apparently hating his parents legacy and then ruining it in the public eye, and then BAM, when the manor comes down on top of him, he's suddenly all weepy and repentant about it for some reason, even though what's happening is not remotely his fault, and even though he has previously shown no desire to give a damn about his parents legacy, and in fact just broke up an entire party where there's a fairly subtle flash that he MIGHT have given a damn about what Fredericks told him re: apples and trees, but hardly enough to be that weepy about things.
That's very vague character development, and a completely unneccessary moment in my mind. It's equivalent to the children's movies where characters suddenly just "change their behavior" for no reason at all so they can learn a lesson.
No, we can't just show Alfred patching Bruce up and show Bruce's determination to go on despite Alfred's objections and then Alfred standing behind him, we have to show Bruce uncharacteristically sink into despair just when Gotham is screwed if he does so.
Something appropriate would have been...well, frankly, not having Bruce hate Wayne Manor and what his parents represented to begin with, as that's fairly out of character anyway, and a disservice to the character overall. "This house is a mausoleum"? Hey, way to be a student of the comics, Chris and Dave. Maybe a nice visit to the grave of his beloved parents? Nah, it's more "realistic" for him to hate them...right on.
Corporate/politician Lex is just a Kingpin ripoff without what REALLY makes him interesting, and that's his motivation for hating Superman. I can't believe you would dismiss the entirety of the film just because it's real estate Lex. Real estate Lex did things we've all wanted to see ANY Lex do for years, and Singer and co get props for that.
-Who cares if the bimbo turned on Lex? If she didn't, he has Superman's crystals. Do you WANT Luthor to have Superman's technology?

-Don't forget "Stanford". Would you prefer nameless lackeys? At least Luthor's had SOME personality to them, and weren't just completely stock thugs.
-Lex Luthor has always had bimbos. Always. And I mean always. And he's always "used" them. Her presence was one more way to show just what kind of a man he was.
-Wigs aren't really that big a deal, as the man was clearly bald, was depicted as such most of the time, and only used his wigs as disguises.
-Lex Luthor has always been about real estate, and some of his biggest coups in the comics involve landgrabs (NO MAN'S LAND, for instance). He was about land AND revenge in SUPERMAN RETURNS, and the nature of his revenge far outweighed his actual plan. So who cares if he thought he could make a few bucks on the side. That's very in character for Lex Luthor.
The entire point of the SUPERMAN RETURNS Lex Luthor is that he doesn't strike you as a threat at all at first, but little by little you see what he's capable of and then just how far gone he is...and then he's just the meanest SOB you ever saw and downright evil. It isn't perfect. But there's value there.
It's Superman saving the damn world. This is one of those things you just...get...or you don't. You don't need to set up "Superman is going to die" for an entire film for it to be powerful when it happens, nor do you actually have to completely LIKE everything he does to see his actions at the end as a noble and amazing act, period.
If you didn't like Superman getting beat because he...what...left Earth and didn't tell Lois...I don't know what to tell you. Personal preference, I guess. I FORGOT YOU NEVER MADE A MISTAKE!!!
Points for the reference...