Alright I am going to say this because I really want to and I don't think I've established how much I hate Sasuke and why he ruined a series I really liked. I know I've already said that I hate Sasuke but bear with me here, I think I have something new.
Why do I hate Sasuke? Is it his personality? Yes, but there's more to it than that? Is it because he ruined the series? Yes, he is the cancer of Naruto, but why exactly does he ruin the series?
Because he destroy's most everything interesting about the manga. That is why I hate him. He kills off the villains who had potential (Orochimaru, Deidara, Itachi, Danzo). I know Itachi was going to die eventually but you can't deny he bit the dust sooner than expected. He takes away paneltime from character infinitely more interesting than him. (Rock Lee, most notably but there were others). I get that he is the deuteragonist (2nd most important character) but does he still need 100+ chapters focusing mainly on him? Especially when there are so many other characters with potential.
Naruto's greatest strength was its large and varied cast most of whom have been ignored in favor of Sasuke. Kishimoto lost interest in the aspects of his series I actually found interesting and has focused on things I don't care about. That is why Naruto is a waste of potential for me and many other people.
Now people have said that Naruto's cast is so large there is no way Kishimoto could focus on all or most of them without people losing interest. I'm just going to say that's not true. Not I don't think it's true, not I disagree. That's not true. I have read other series with very large casts where the mangaka has been able to keep track of the various characters and not give one or two characters the vast majority of focus. Examples include One Piece, Fullmetal Alchemist and Negima. He had all this time he could have focused on the other characters.
I remember the great arcs, Chunin Exams, Sasuke Retrieval those were the arcs that made Naruto popular. And I see why they were popular because there were so many characters, that if you didn't like Naruto you could just like Shikamaru. If you didn't like Sakura you could just like Hinata. If you didn't like Sasuke you could just like Rock Lee (Glorious Lee!) Naruto doesn't have that anymore because all of the other characters besides maybe Shika and Gaara are pointless now. Kind of depressing because they were interesting, likeable and had potential for interesting stories. Great job Kishi, good going. I'm going to read series where the writer actually puts out consistently good work. I'm off to read Negima.