I'm with Barles. I just wrote a post about this subject in the anime forum. The rasengan and kage bunshin are extremely dangerous in the hands of a capable fighter. In short, even before the Sage training, Naruto was a decent fighter with poor concentration and chakra control. But he DEFINITELY improved in both respects after the time jump, and has since studied those skills in depth with the toads.
A steady stream of kage bunshin wielding rasengans can keep even the strongest fighter from standing still a moment, let along thinking up a plan. Meanwhile, Naruto (or a clone) can think of a plan at his own pace. We saw this much with the Kakuzu fight.
Sorry for the double post. My internet connection is acting weird.