If Riku and Sora used to be as good as each other (I dont remember where I heard that, maybe in Destiny Isles) I very much doubt Riku would "die on the spot" as Shadowrise said. AND I very much doubt; a keyblade wielder, and person who has been in the World of Darkness for a long enough time, and someone who's been hanging out with Mickey, would get beaten that easily. And just because you've only SEEN three of Riku's skills, doesn't mean he doesn't have any others.