Changing the main character looks?

[Let's Go Fearless!]

I found this interview of Toriyama where he said that his stuff doesn't want to change Goku's appearance and how this goes with other shonen manga/anime as well.

I see. So then after that, Goku grew up…

Toriyama: "I got a lot of pushback on that at the time. Apparently in shōnen manga changing what the main character looked like was a big no-no, but I didn’t care about that. His head/body ratio made fighting hard, so I said that if the series was going to start focusing more on battles, then I needed to make him an adult. But this really shocked them: “The series has finally gotten popular, and now you want to go and change everything!” That was the kind of reaction I got."

https://www.kanzenshuu.com/translations/dragon-ball-super-history-book-akira-toriyama-interview/

So does other anime/manga have thins problem?

 

[Captain Cadaver]

Not really. Prior to DB, it was the standard for main characters to keep the same appearance bar artistic changes even if going through a timeskip, with the only real exception being JoJo's Bizarre Adventure ageing Joseph up in Part 3 around the same time DB went into the 23rd TB. After Dragon Ball made this change, it become acceptable to have characters drastically change their appearance in Shonen such as Sakuragi's haircut in Slam Dunk or Naruto's physical growth after the timeskip.

In other words, no Shonen series tried it before Dragon Ball and after DB did, most series that followed it wanted in on the action.