No, really. I think that young adult authors everywhere owe Stephanie Meyer a debt of gratitude - and I don't mean for setting the YA fiction bar so low that we can easily step over it. I honestly think that she deserves praise.
She has created a story with no discernible purpose. Twilight is not full of important life lessons (unless you count old men hanging out in high schools and going after jail-bait is romantic or necrophilia is A-OK), it does not reach its readers to be better people or force them to think critically about the world. What Twilight does (though I'm sure many will argue this) is entertain*
When I was a child, the thing that irritated me most about children's fiction was when the author referred to adults as "grown-ups". In my mind, adults were adults - and only an adult would ever think of calling them anything else.
As I progressed into reading YA fiction, this feeling of being shortchanged remained - still caused by the obvious attempts of an older author to sound much younger than they were - like they were in disguise, trying to make their insights seem more palatable or their wisdom more realistic. In most YA fiction that I've read, the authors blow their covers in two ways: trying to use language that makes them seem young, which, unless it's done with extreme skill,tends to come across like boy, this sure is funky - and with platitudes passed from the main character-puppet from their soapbox, right at the end of the story: She realized that her parents really did only want what was best for her.
Where Twilight succeeds, and where other books since have excelled, was with shrugging off the idea that YA fiction should be in some way appropriate. There is some wisdom in the idea, in terms of parents being the ones who pay for the books and are, in theory, monitoring what their kids read - but Twilight (and a lot of the books that have followed) don't shy away from dark subject matter, and aren't afraid to stray into the realm of the ridiculous. I'm not saying that Twilight is the first YA novel to take this route, just that its popularity has made it more acceptable to be taboo - and, yes, I acknowledge the inherent irony.
The thing is, I don't think that YA fiction has to do anything. Our job as fiction writers is to tell the best story we can, in the best way that we can for our audience; it is not to raise other people's adolescents or police what young adults are reading and have access to. If we can impart a lesson or two and avoid emotionally scarring our readers in the mix, that's just gravy. I'm not saying I'm going to go out and write a bunch of quality-free YA pulp, but it's nice to know that the choice is there for me.
And if I want to write an ultimately meaningless piece of reader-gratifying fluff, I have that option.
*Not me. But it must entertain someone.