Ryan and I are discussing this for a long time. The core docs has as much working examples as possible (because Ryan wants that).
I think it's good to have some more readable examples when using advanced formats. For instance, I don't believe people who didn't have knowledge of XML will use it: (a) yaml is always easier to understand and (b) yaml is always before XML and (c) if they don't use yaml, they will use PHP because that's more familair.

I think the only people who use XML are people who know XML or people who write open source bundles (because XML is validationable). So I don't think it will be much of a problem to use advanced things.