It's also important to note that a character can become a Sue over time. I think Honor fits in this territory. She had character flaws and meaningful opposition for probably the first half of the series. Even some of the talents, with the dueling pistols and the swords, were given decent foreshadowing. That started to change somewhat after becoming a fleet commander. By that point, most of her character flaws had been dealt with. Tom Thiesman and some of Honor's protégés were more interesting characters after that. I agree on the latter two, but I'm not sure when Luke failed or really struggled in A New Hope. He blew through obstacles with ease about the same as Rey's. Come to think of it, I can't recall any real flaws in the first film, except perhaps some whininess in the beginning. Those, such as a certain degree of overconfidence, came later. I'd imagine the same will be the case for Rey. Hopefully it isn't done in the same way; we need innovation not regurgitation.
I have to admit that I saw a Mary Sue used effectively once. It was in a novel by Lilith St. Croix. I'd have to dig for the name. But it really, really worked. I sort of agree with you. I guess that the problem is that with the knowledge of impending Mary Suedom, a reread is almost impossible. I couldn't even make it back through On Basilisk Station the second time around, because you could see the seeds there.
If it really really worked than by what standard are you calling it a Mary Sue? She was too good? Apparently not, because it worked. The defining aspect of Mary Sue is the nigh complete sacrifice of good story for the sake of idealizing the character. If that sacrifice hasn't happened and the character's presence adds to instead of subtracting from the quality, than it can't be a Sue. That's the ultimate difference between unlikeable character and Mary Sue.
I want to read a book where an author intentionally makes a terrible Mary Sue, but then breaks the fourth wall, takes him/her into the real world, and ruins the Mary Sue's life.
Heh heh, not a book but " The Last Action Hero" with Arnold sort of does that. More about the ridiculous movie things that wouldn't work in real life, but you get the idea... bad movie though. Bad bad movie.