Sounds about right. People complained about Batman appearing so late in
Batman Begins; as an origin tale, that's appropriate. They may have complained, but we know they all liked it deep down.
Two others things. I'm OK with this being an origin. As long as they stray away from showing too much of Krypton at the beginning, and too much of his life on the farm before he sets off. Matter of a fact, those are best avoided until later. They reek of "been there before". There's all sorts of opportunities to show Clark developing his motivations. . . wandering around Africa is the popular idea right now, and it'd work.
And I do like your idea of Metropolis being a mess before Superman shows up. Show it being almost as bad as Gotham. Batman could only clean Gotham up so much because he's a human with some cool technology and the willpower. Superman is a different story altogether. He has awesome super-powers, he needs to use them, embrace them, and make zero apologies for it. I get this sense that writers make those matters too difficult for Superman, because they don't want us human readers to feel overly inferior or something.
Screw that. Superman uses his powers to his full advantage. In the end, the audience wants to be awe-struck. Who cares if we know we could never have the same powers. Superman is only something to strive for morally. Everything else is supposed to be pure entertainment.