I've read my novels for this month! I'm prepped and ready for discussion, notes, and everything else I need to document to show that I'm on top of things, synthesizing, and doing the work.
This month, however, the novel that we're reading and discussing is . . . by our teacher. AWKward. Further awkwardness: Said novel stars a Mary Sue. Yes, friends, a Mary Sue. By the end of the book, I was smacking my head against the back of the couch (in lieu of smacking the character) and thinking to myself, "Of course she won the Grammy and started a fund for children! She's just that perfect. Her only flaw is being loved too much."
I love me my female characters: I write them all the time. Mine are generally flawed specimens, but I like heroic: Buffy rocks! And it is entirely possible that my perceptions of commercial fiction are skewed. I'm a pretty omnivorous reader, but it's been a while since I've read your basic plot-driven page turner. I realize it's all about what happens and getting bogged down with the finer notes of character development on this locomotive is somewhat beside the point.
But I submit that when your central character is beloved by all--even by violent people who have reason to be pissed off by said character--and all your other characters exist to revolve around, tend to, talk about, and rescue your central character, you have a Mary Sue on your hands.