If you want to decorate JBoss Metadata with interfaces (in a spi package ;) ), I'm fine with that. It is partially decorated already, there are a number of interfaces used.
As is, the xsd is too convoluted for automated generation, and is sometimes wrong :( We went from one problem to another one last week. Everything should be much simpler with explicit min/maxOccurs on each element if they are not the default, and it would make generation much easier obviously.