OK, time for me to get a few things pointed out.

1) My evidence for the dislike of Ukyou by Darren Demaine was his
comment along the lines of "This is it for now; I'll throw up (sorry,
*think* up) something later.  That sounds to me like an author who
is reluctantly writing a character.

2) No one is arguing that Ukyou has been canonized by the fanfic
community.  However, I really don't see what the harm is.  If we
were to stick to precisely the characterizations and evets that
Takahashi-sensei wrote, the fics out there would be extrememly
BAWWWRRRING! (To quote Shampoo) (Jacqui and Carrie, not the Chinese
girl).  F'rinstance, how many Ranma fics out there feature Dr. Tofu
in a fairly important role?  He's in most of the best continuation 
fics that I've read.  And yet Rumiko-san gave up on his character
fairly early in the series.  Writing someone in character does not
mean locking them into a single set of moves.  It means that you
don't have Ranma socking Shampoo or Kasumi saying "F**k, yeah!"
Even an occasional OOC role might work.  In my first fanfic, I had
Ukyou commit suicide.  No, I don't think that she would.  But I
wanted to examine the repercussions, so I wrote her a little OOC.
A few people complained.  Oh, well.  In other words, if I want
Ukyou to be better than Takahashi-sensei wrote her, then I'll
believe that.  I do get irritated at people who say she's a violent
bitch like the rest, just as much as I get irritated by those who
think Ranma loves her more than Akane.

Look, there are currently about 50 different fanfics that wrap up
the series, none of them in the same way.  Some have Ukyou depressed,
some have Ukyou pairing with Ryouga (a fanfic invented scenario if
ever I heard one), some even pair Ryouga and Kodachi, a pair that
still gives me nightmares.  I hold all of these fanfics in my head.
When I read the next Furinkan Summer, I'll go OK, depressed Ukyou
who's getting better, and disguised Tsubasa courting her.  In the
next part of After All This Time, I'll switch to Mood Swingy Ukyou
who's discovering a latent attraction to Akane.  And in Kun-chan's
series, we haev the utterly happy Ukyou who's pregnant, married to
Ryouga, and thus is rather difficult to write controversy for. :-)
Just because Rumiko Takahashi didn't want Ukyou to be nice doesn't
mean I can't write her that way.  And others write her that way, 
too.  All the time.  Now, if there was a fic where Ukyou decides to
slaughter Akane and her sisters to get Ranma, I would balk.  There
is such a thing as *too* out of character.  (As the recent spate of
Ryouga goes bad fanfics show).  But fanfiction is about discovering
hidden aspects that you think are in the characters.  If Ukyou is
good or bad, that's great.  But don't let the characters remain
stagnant.

What I'm trying to say is that it's not whether Ukyou is sainted
or evil, it's the "Well, she is this, so stop believing what you feel
is right.  Kun-chan has tons of problems with Ukyou.  I haven't seen
the characterization in her lemon series affected by it.  Hell, Shampoo
is living happily ever after in a series of KUN-CHAN'S!!!  If you
don't develop the characters, even if it's only in your mind, you end
up...didn't we have this argument with Ryan Mathews a while back?  
It's one of the reasons I avoid his stories...anyway, I like Ukyou.
I mention this occasionally.  I don't yell at Kun-chan when she says
otherwise.  I've even managed to keep my temper when people insult
Ryouga.  No-one's attacked Akari yet, so I can't tell what my reaction
would be.  But in terms of fanfics, let the characters develop.  Let
Ukyou be better than she was in the manga.  After all, to use one of
my favorite quotes:

"Do I contradict myself?  Very well, then I contradict myself.  I am
large, I contain multitudes." - Walt Whitman

--Sean Gaffney
--If anyone can translate what I just wrote into logical phrasing,
--more power to you.