It isn't just the motivations but what what those motivations mean about a character and how it establishes/shapes a character's traits.
Characters who are simply incapable
of learning or using a person's a correct name tend to be absent-minded, frazzled, eccentric, or are otherwise quirky and peculiar in a way (and are more likely endeared for it by a viewing audience).
Characters who deliberately call someone else by a wrong name
or just don't bother to remember what the correct name is
tend to be dickheads who are abrasive with others and may have an overinflated ego (even if such characters have other traits that may make them likable or sympathetic, they're still usually some variant of the Jerkass
trope, pretty much, by default).
Even if the two distinctions don't get separate pages, I do feel that this is good enough to push for a soft split (and, given the page in its present form, these are really the only two subtypes that I'd say are worth mentioning).
edited 18th Feb '12 9:07:10 AM by SeanMurrayI