Teclo said: I see what you're saying, but then you could also say "Why does Kyonko have a ponytail added (when it only serves to lessen the resemblance)?"
Well duh. Kyon/ko likes ponytails. :)
I'm more inclined to ask how Kyonko could miss the Katana when she went into the classroom. Asakura's knife was so shocking because it came out of nowhere...
the (brown) cardigan is a sweater, for keeping warm - optional item. Since the male uniform has a blazer, there is no need for a light sweater. The option is to take the blazer off if one feels too warm.