Deleting parts of the generated code is one of the easiest ways of customizing. There is just one cognitive task that you need to do - decide what you need and what you don't, I have no data about that - but I am sure that converting of you internal thoughts to the programming language syntax is much more complicated.
I think this is one of the factors that makes code generation an efficient tool in some circumstances. When you close the logic in some library, you cannot modify it so easily. This is one of the reasons that in Catalyst::Example::InstantCRUD I finally decided to generate the templates, and also to use a minimum of logic there - so that deleting, and also changing the order of some elements would not break it.