B
It‘s because people want to see too much blood nowadays. They want MCs who slaughter their enemies brutally and not talk to them instead of fighting. Personally I prefer the latter, but many just don‘t lol.
His struggle to find a way to defeat Ozai without killing him lasted how many episodes? And Avatar doesn't have that many episodes anyways so Aang's struggle lasted a substantial amount of the 3rd season.
I have no opinion on Naruto's character. I just don't like the German dub