Christopher Angel wrote:

Frankly folks, those of you who took this essay to heart, remember that
Mike did say that he reserves the right to be wrong.

He even quoted fics that work against his arguments.

Not to toot my own horn here, but if half the C&C I get is right, there
is a LOT of room out there for fics where a new character takes over the
plot.

Hrrrm.  Not as much as you might think given that the thrust of the
rule was that you shouldn't sideline the characters of the source 
series.  

Two things to bear in mind:

1:  Some fics are good in spite of having an Annoying New Character.
They'd be better with an Appealing New Character, but you can't
have everything.  It is for example, possible to write a story where
Nabiki, or Urd, or any of Usagi's Merry Band, fall in love with an
Annoying New Character (or suddenly pick up one as a sibling), and
write Nabiki/Urd/Sailor Bimbo so well that that the annoyance factor
is outweighed by quality character development in the other character
or characters.

2.  I would say every single New Character (spear carriers aside), 
appealing or annoying, will strain one at least one of those rules in 
the original essay.  I would also say that there is NO way that a 
Character could break all of those rules and yet be anything except 
intolerably annoying.  Every dog gets one bite.

3) If he does have a major affect on the plot, make it reasonable, and
DON'T focus only on him, unless it's necessary.  Siblings was as much
about Ranma as Andrew.  Shieldsman focussed on events for which Crimson
was present, but the changes in the others was as important as the
actions he was involved in.

And thus, although you may bend the rule about New Characters taking
center stage, you don't really break it, most of the time.  

I have more, but these are my major ones.  But then, I break these too...