Naruto placing all his happiness and goals around saving Sasuke is what stunted his character.
It was the one thing that urked me so much...and what is even more urksome is after Sasuke was saved....Naruto basically stopped caring. "Sasuke no longer wants to destroy Konoha. Doesn't matter if he spends 12 years away from Konoha because I did my job and now I don't care."
Seriously. we were nailed hard almost every time Sasuke was on screen about how Naruto had to drastically save him or the whole world was gonna blow up...and after that it was like "meh. Who cares?""