I dont agree with all the naruto is stupid stuff. He is immature, and has the personality of a 5 year old, that much cannot be denied. But he is hardly stupid, as proven by how he has handled the battles with Zabuza, Kiba, Neji, and Gaara, as well as his amazing use of rasengan in the water battle to save everyone.

This just means that despite being a great tactician, if you cannot keep you emotions in check there is no way you can pull it out. It also means that rather than naruto being stupid, it is the author that is stupid, almost ruining a great character just because he is too lazy to come up with great smart battles like the ones before.

If you think about it logically, naruto defintely has mastered the kuchiyose no jutsu for frogs. It just wouldnt make sense if he learned the technique in such a short time and still isnt able to use it after all that training with the ero frog king.

Some people might argue that naruto couldnt even master rasengan, but rasengan is not just some normal technique. It is a killer move that the 4th, a genius ninja, came up with. He did in fact learn it in a week, but that is only because he cheated and used kagebunshins. It just makes sense that without the KB, there is no way he could overcome the last and hardest part of learning rasengan in such a short time.

I dont think its a good idea for naruto to be suddenly aware of a ton of jutsus, and how to break genjutsu and stuff. It just isnt naruto. Indeed characters can change, but such a change would go against the kind of person naruto is, and would lead to the loss of his appeal in the 1st place. His intelligence isnt like sakuras and sasukes. It is in fact more strategy than knowledge, and it was amazaing how he survived with just that.

EDIT: not being able to use the technique doesnt mean you cant teach it. of course the hiraishin is not a sure thing yet, but it isnt too far fetched for kakashi to know how to do it since he was the 4ths student. There is probably just certain restrictions that prevented him from actually using it. (chakra maybe?)