Fiery-tempered Kyou is an appropriate character for depicting aggression and defiance. After all, not many people would suggest 'Battle Onigiri!' as an activity for a school festival. Kyou's perhaps less representative of the third trait of the Seven of Wands, conviction. It's a quality that he can always develop later though, right? I've read some of the Fruits Basket manga, and I'm confident that it will happen.