Graphics Horse
Member
To some degree it was apparently what worked better with the gameplay and overall style they decided to go with, but I wouldn't be surprised if focus groups did basically say "go deeper", and they looked at HOW to best do that.
Either them or just EA management in general.
Then again, when I think about Insomniac I usually only think about their cartoony games, and forget about the .uh, less cartoony games.