I mean dude if your looking at Naruto for great or even good character development you might want to look elsewhere.
Though I would recommend you Tokyo Ghoul a Seinen that has really really great character development. Probably one of my favorites if not my favorite so good.
Yeah I know I'm pushing this series so hard, but damn is it so fuckin good. Everyone needs to read it.
No shit. I know this already, I wasn't expecting great character development or anything just consistent character development. It really doesn't make any real sense why Sasuke wants to do what he wants to do after he changed his outlook when Zombie Itachi talked to him.
Plus he already killed the man responsible for the Uchiha massacre, so why would he still want revenge after that? Things just don't add up at all, and yes I do realize Sasuke had those motivations to destroy the "Leaf" after Danzo's death, which is still abysmally stupid and senseless.
If a character is going on a quest of revenge there isn't any real logical reason why someone like Sasuke would go beyond that. Sasuke's character development is basically, "Now I've had my revenge, now I conquer the WORLD!" which doesn't really follow any semblance of logic from what Kishimoto has written about Sasuke in the series.
If they should battle - Naruto and Sasuke - it should be a battle over who becomes Hokage. Maybe then Kishimoto could write a thing where Sasuke falters in the battle, finding regret for all the terrible shit he's done in the past and perhaps turning him into some type of shinobi jail or perhaps full on suicide for his sins.