My viewpoint on characterization in fanfics is that though it has
to stay semi-in canon, if it wanders from it, there better be some new 
insight that no one's thought of or something logical to happen to change
the character.  Hitomi's "A Son's Duty" is an example of the first,
Nightelf's "Sunrise" is an example of the second.

Foxtrot the Furryous