Another thing that we can always say about files, especially XML files, is that they evolve. When (not if ...) they do, what’s going to have to happen to your clever-but-delicate contrivance, and why? Presumably you are still asking the same questions and still doing the same things, but how much does the source-code have to change, and how pervasive is that change?

whose contrivance? what module are you referring to? perigrin's? well, with XML::Toolkit there are a set of classes to generate XML and similar to how a ::Loader for database constructs classes for databases.

So, your code itself would change very little because the classes are there to build the XML ... just re-run the loader.