I agree that fixing code based on the AST is much more powerful than applying some regexes in the code. And once PHP_CodeSniffer 2.0 is out with this great feature, I'm quite sure the Symfony team will look into using it (not an official statement here as I haven't asked other team members). But in the meantime, applying the PHP-CS-Fixer is eaiser than doing everything manually, so I'm using it