When two syllables are too many

I just don't get it. I mean, I don't like uncanonical nicknames (in fanfiction! They're fine by me in fannish debate) in general, but if the canon name of a character is lengthy, I at least understand the impulse to shorten it so one doesn't have to type it out all the time. (Special case in point: Rumplestilskin, who was called "Rumple" in fandom before characters on the show started to use that nickname, too.) But when a character has a really short name in canon, like, say, Kili and Fili, why the need ot make it even shorter? Seeing "Kee" used in the summary is guaranteed to make me not read the story in question, by the way.