Everyone has a style; those stiles could conflict with popular portrayals of characters or entirely butcher them without meaning to. I have my own style that I wouldn't dare put on characters I like that are canon. It's just easier to make an OC character and fit with that.

If people happen to do canon characters and I know any thing about them, I expect a very "realistic" (sometimes a word that must be greatly bent in fantasy, eh?) portrayal of the character or it just ruins it for me.