Much Ado About Sue

So I've been working hard on Fleeting Dragons, which ties into my Great Fox comics (I'll have something to show for it sometime this year, I swear), and dwelling on a dilemma that's been sitting on a shelf in my mind for several years, now:

Is it possible to write a good Mary Sue?

The forthright answer seems to be a glaring no--it's a contradiction in terms. By its nature, a Mary Sue is an original character gone horribly wrong, and the best way to write one well is not to write one at all. I can't think of a single original character in any fanfic that I could positively identify as a self-insert/Sue and simultaneously not hate to death--but was that because of the principle behind the character's creation, or the way the character was integrated into the story?

It doesn't take a long shot to guess that I'm thinking of Mishu/Myshu, who has been a major character of my Phoenix Chronicles from the start, and from whom I derived my online handle--because I was fifteen and thought she was cool. Isn't that how all Sues get started?

So the question hasn't been whether or not Myshu is a Mary Sue; there's no point deluding oneself (she bombed the litmus test at the very first question.) The question for me has been whether or not to keep her--whether or not her very presence would compromise the integrity (haha) of the plot and drive away anyone who might otherwise be interested in a somewhat decent adventure story.

When I went into (re)writing Dr. LEA's Diary this year, I seriously considered writing her out entirely. While that could have been accomplished with minimal damage, I felt like that would be removing the most tangible link between that story (and consequently, the cast of CT) and Fleeting Dragons, not to mention the core quest of the series: the search for the Phoenix.
It would entail rewriting the entire series with a new set of motives for half the characters, finding another character to provide the impetus for their quest (and who's going to have both the position and the give-a-damn factor? ...Magus??) and finding a different way to relate the reader to one of the major races/antagonists. It wouldn't be easy, but it's not impossible, and can probably be done with favorable results.

But do I WANT to? Do I want to throw away a character I've been working with for ten years? Is it truly impossible to write her in a way that is both interesting and supports the story--or at the very least isn't a terminal brainsore?


...Hmm.