You like it? It's one of my very favorites. That's important to know, because I'm about to bag on one of the characters, but do understand: I love this book.
So, Peeta. He's perfect, isn't he? Strong, sensitive, artistic, and willing to do absolutely anything for the girl he loves--even though she's never shown any affection for him (the opposite, actually) and has few redeeming qualities whatsoever.
Not that I don't like Katniss. She's an awesome survivor, and she takes care of those she loves. I just don't see what Peeta sees to make him repeatedly sacrifice everything for her.
It's not just Peeta. I've read a number of recent YA novels in which the protagonist inexplicably gains the affections of the Perfect Guy, and keeps them even though she's very clear that she loves someone else, or at least doesn't like him. Sometimes he wins her over, sometimes she feels she doesn't deserve him, and sometimes he tragically dies for her. Oh, so tragically.

Just like real life Bad Boys are not often redeemable (sorry, ladies, they're just jerks), so real life Nice Guys will not wait years and years, sacrificing everything they have until the girl who obviously doesn't like them comes around.
Sorry, girls. There are nice guys out there, but we're not all strong and handsome, and most of us will move on once we've been spurned. (We're nice, not perfect.)
If you love the Perfect Guy trope, or you're writing it, don't worry. It's not Wrong, and I've never hated a book because of it, just rolled my eyes sometimes.
It's not hard to fix either: give the boy flaws. Peeta's problem was he was too perfect. His greatest weakness was his inability to see how perfect he was (which: really? not a flaw). Real guys are sometimes a little arrogant, a little vindictive, a little dishonest. It doesn't make us jerks or bad guys, it just makes us human, believable. Believe it or not, it works in fiction, too.
Have you noticed the Peeta complex? Does it bug you, or (like most things) is it just me? Let me know!