I don't think Naruto is nothing without the Kyubi, Mut@t@... I still think he'd be at about Kiba's level, minus the dog. Hypothetically. And maybe he'd think a little harder (instead of always acting like an idiot) if he couldn't just beat everyone he knows with his Kyubi advantage? I think he wouldn't be as arrogant as "I WILL BEAT YOU I AM NUMBER ONE" all the time if he got smacked around a little more. Maybe losing this fight to Sasuke will humble him a little. I hope so.