Yeah sure Jiraiya's training was rasengan, how to disrupt chakra when under genjutsu, and all the other stuff that we were never shown. I mean you cannot honestly believe that in the 3years that they were together, Naruto only learned the Rasengan. Also Naruto learnt how to perform the rasengan the first time they went out of the village together, to get the new hokage, so it stands to reason that they focused on other things when they went again for the second time, when the time skip happened. Don't be an idiot.
Kakashi came in and helped Naruto move on to his next level where they would be utilising nature manipulation. And as it was explained, clones increased his experience, so no problem there.
Fortunately Naruto hasn't had only one master, the toads came in and they taught him how to use sennin mode. THat took him a little over month to a month because he was driven. Jiraiya never really had anything pushing him besides wanting to bang Tsunade, Naruto however needed to learn this art or his life and the life of the other villagers was on the line. Because he was driven by revenge and wanting self-preservation he took the training head on and came out tops.
He fought with the Kyuubi under the guidance fo his latest master, and because he had become as powerful as he had, he succeeded, although he did need some help from his mother. Nothing about that was far-fetched and overpowered. He used the powers he had and overcame the kyuubi. End of story.
THen the same can be said for the Rasengan, Rasen-Shuriken and Sage mode. They are the techniques that we know and unfortunately because Kishi doesn't want Naruto revealing his techniques yet, they are the only ones we will see now. He used them just as effectively in that fight because they were his arsenal and for now we don't know any other. I don't get what yu are on about on tis point though. So now you have a problem with the techniques that Naruto uses and how he fights? Do you love sucking Sasuke's **** that much?U_U
THat was not a short time, and if anything this has happened in the same time frame as Sasuke gaining his powers.This is the pattern and whether you lke it or not it is not going to change anytime soon.
Sasuke - Chidori = Rasengan - Naruto
Sasuke - Kirin = Rasen-Shuriken - Naruto
Sasuke - Mangekyou Sharingan = Sage Mode - Naruto
Sasuke - Eternal Mangekyou Sharingan = Kyuubi Mode - Naruto