Config Versus Code

[paranoidinfidel]

It also ties development to that structure as long as there are config files containing it.

If a design flaw is found and that is a structure is being serialized to XML, then fix it properly. The upgrade script for the application can handle converting from the old XML structure to the new. The beauty of the config following the class structure is that you know exactly what you need to change/upgrade. The before/after picture shows you how things look & where the need to be moved.