I don't hate Sophie, but I think she has a lot of issues with the way she's written. For example, her raging case of Not Like Other Girls.
Don't get me wrong, I have no issue with a tomboyish character, but the fact that all of the other characters are very stereotypically feminine.
My other main issue with Sophie is that she's very bland, and the idea that Shannon made her bland so we could project ourselves onto her is... dumb. Really, really dumb.
Marella and Dex are fan favourites, right? Marella is a spitfire, she's sarcastic and loves gossip, but she can be mean and feels betrayed when she's left behind. Dex is a bit sarcastic, but he's pretty quiet and helpful, and he's lovable because of how much he cares about Sophie and the others. He's also somewhat smug and seems to be slowly becoming more and more introverted as the story progresses.
You can clearly describe their personalities. Now try to describe Sophie. I'll try too.
Um... she's clumsy, she's a bit mean, and she doesn't like girly things.
In eight books. This is all I, someone who somehow managed to get two hundred words out of analyzing Silveny, have figured out about Sophie.
Also clumsy isn't even a personality trait. It's just a thing that happens to some people.
I do feel like the Mary Sue abilities could be done right, had Sophie been written by a more practiced writer. I think that it would be quite interesting if she had destroyed the Black Swan's expectations. Rather than thinking humans mattered, she could have become extremely cynical and mature from knowing what everyone thought about her at all times. She would get into less danger, and she wouldn't give a singly heck about humans.
Instead of following the clues to find the Black Swan, she might decide that she does not want anything to do with her stalkers. Maybe her friends would be more curious and kind of ringlead the investigation.
Also, can she just... have less friends? It's dumb, and most of them are boring. *cough* Fitz. *cough*
Same thing about the love triangle. It's really dumb, and honestly seems kind of like it's on the brink of being unhealthy. I think all of them deserve better. Fitz should have a calmer, more reliable partner to balance out his anger. Keefe needs someone who can be his impulse control. Sophie needs... well, Sophie needs to get a personality so I can figure out what kind of partner she needs. I mean, Fitz needs a better personality that doesn't revolve around Sophie so much (which is how I know Sophitz is endgame BTW) too, but still.
If you have any issues with this, please let me know! I want to try my hand at rewriting KotLC, and I'd love to hear your suggestions.