I think part of it is this displays how Naruto isn't exactly the greatest skilled Ninja in the world.
Instead, through sheer willpower and determination he is able to compensate for his lack of natural talent with simple determination! Of course clones and a large chakra pool help out XD!
In any case, that was before Naruto posessed Sage Mode, Kyuubi Mode, and Bijuu mode. Obviously, some of his stats such as speed and strength would have improved immensly by now. And at that time, Sasuke was probably stronger than Naruto.