Something to note is that the shadow clones were used in situations to surround and outnumber an opponent, to make a chain to catch Naruto and fling him back onto a platform whenever he fell off, or to pull himself out of danger. To begin with, when he uses shadow clones for those purposes, he already knows pretty much exactly what's going to happen, so he has it visualized beforehand. So the memories from the shadow clones would probably just mix with the memories of him quickly planning it out. On another note, those clones aren't usually around for very long, so the information they gather is minimal to begin with. And when he uses them for Rasengan and Rasenshuriken, they have a very specific task that they concentrate on before disappearing. Essentially, they work on an aspect that ideally, Naruto should be able to do all by himself, thus making their fleeting memories an expected, though rather "fodder in the backround" result.
Kakashi was the first person to show Naruto what the jutsu was actually meant for. Before that, Naruto only used them in close combat type situations where everything went too fast for him to actually sit down and absorb the information before continuing. Because, theoretically and logically speaking, the more clones that are made, and the more information they collect, the longer that it should take the original to consciously sort through all of it. And since Naruto isn't the type to do that, it just gets shoved to the back of his brain and forgotten, like what you had for breakfast yesterday, or the words in the middle of the last chapter you read in one of your favorite books. Sure the information is there, but since it has very little relevance to the task at hand, whatever that may be, it gets ignored for the most part. And yes, in most cases, little details have very little to do with whether or not Naruto can smack Kabuto in the gut with a Rasengan, or whether he can smash a Rasenshuriken into Kakuzu from point-blank range.
Well, that's my take on it anyway.
So many people tend to forget about this.
