[microtonal]

but the more simpler you get the less there is that end up biting you

And increasing the probability that you invent the wheel, badly. I have been using libxml and libxslt for years and as far as I remember I never encountered a bug. Both projects have been developed for years and is used by a gazillion other projects.

It is many times more likely that you will be bitten by a bug in your own custom configuration file parser than e.g. in libxml2.

I am not arguing for or against XML, but code reuse. Simplicity also means not reinventing the wheel and keeping your own projects simple by leveraging existing, good, libraries.