Sometimes I get the feeling that whenever a reviewer doesn't like a YA heroine they simply accuse her of being a Mary Sue regardless of whether or not she actually passes the litmus test.
Mary Sue is now the equivalent to 'I didn't like her.'
I wonder if it is related to bitchy high school behaviour. It certainly reminds me of it. It seems a YA heroine can't be good at anything without being accused of being an author insertion.
We call that 'tall poppy syndrome' where I come from. Except sports: boys were allowed to be good at sports without people dismissing their achievements. Every other achiever was mocked for being smarter/more focused/more determined than the rest.
I feel terribly sorry for those readers who were never good at anything in their life.
I get that a lot of the girl characters are Mary Sues who are 'not like other girls' and beautiful without knowing it, but to simply dismiss a character as being an author insertion because she's good at, say, math, or singing, or sports, or anything else prized and that takes actual talent that some people are blessed with borders on jealousy for me.
But you know what? Sometimes there are characters out there who don't trip over nothing and don't need rescuing and don't have everyone be nice to them for no reason and aren't good at everything they try the first time. But those characters are harder to find because they're not in the bestsellers.
I think the masses want Mary Sues.