I think replacing songs in the dub can go pretty hard, like, that's how we got most of the iconic 90's american anime theme songs. pokemon, digimon, yugioh, etc. I do like a lot of the naruto OPs too, for the record, and soul eater, and fullmetal alchemist, but it's really hard to beat how iconic the opening to pokemon is, and how that's laser engraved to like a fifth of all millennial's brains.

Actually, I wanna hijack this top post a little bit. Other people have brought up japanese name pronunciation, and replacing the names with more western stuff, and I would like to bring up the decision specifically in yugioh to make joey have a boston accent to mimic the accentedness of the japanese he would otherwise speak with. I dunno, there's something to the 4kids dubs that has a little bit more texture than your normal modern anime dubs. I like the lack of censorship more, the VAs tend to be better, there's not like, big confusing rewrites or repacings of certain sections, all that is good, about your more modern stuff. At the same time, I feel like a lot of the sub vs dub argument is gonna come about more when people don't let the dub be it's own thing. You already have to translate turns of phrase, culturally dependent expressions, yadda yadda, at what point do you really decide to stop? Maybe a bad example, because it doesn't really conform to the spirit of the original at all, but people still occasionally talk about the ghost stories dub. I dunno. I guess it doesn't need to be official, there's always abridged series to fill the void in my heart when it comes to anime that's written for a western audience more, but I do kinda wish that more dubs were just like. Willing to take risks. That more dubs were very obviously stand out.