The problem with XML::Simple (well, one of) when using it to edit a file is that it tends to change the XML in ways that do not make a difference when the file is read by XML::Simple, but will cause all other tools to fail to read it.
In this particular case all those content-only tags will become attributes of the parent tag. XML::Simple will not mind, other tools most probably will.
Not speaking about the fact that your code would not work ... there is no load() or save() in XML::Simple and the data structure would look different than what you seem to think.
Enoch was right!
Enjoy the last years of Rome.