I think in most cases it changes their direction and who they were initially. Many bands changed, I think of Aerosmith and Bon Jovi, etc. They kind of went towards a more pop sound versus their harder roots.
In some instances, with a well known band, outside writing can enhance their sound. Don't producers always assist their clients with writing advice when they're in the studio? Producers like Mutt Lang and others of his caliber command high prices due to the help they give artists.
Producers have a different role, but influence songs or even help write them like Bob Ezrin. I'm ok with that. But look at what Diane Warren did to Heart or Aerosmith. They went from edgy rock to a more pop and commercial sound.
In some instances, with a well known band, outside writing can enhance their sound. Don't producers always assist their clients with writing advice when they're in the studio? Producers like Mutt Lang and others of his caliber command high prices due to the help they give artists.
Thoughts?