Sume Gai wrote:
hikikomori being added sort of made sense as we really didn't have a word that specifically fit the context of someone who avoids social contact but is not necessarily agoraphobic or otherwise disabled.
We don't have a word for "loner" or "shut-in"?

Some Guy wrote:
Kawaii simply means cute, I fail to see context which necessitates it's addition to the English language.
Necessity doesn't really matter, though. Oxford tends to hew toward descriptivism rather than prescription (unlike Merriam-Webster or American Heritage), so its inclusion simply means "there are people who use this word when speaking English", not "this word is useful or necessary" or "we personally endorse this word". And the first statement is true, no matter how annoying we think it is.
Besides, although I don't use "kawaii" for reasons of personal taste, having redundant words or synonyms isn't hardly a bad thing. It certainly makes writing a whole lot less monotonous when you have more options at hand.