I like XML for structured data. I also like XSL for self-documenting format to format conversion (or display). However I am going to respectfully disagree with you about XML schemas, they suck...

XML schemas don't "understand" XML the language, and as a result you cannot use schemas unless you're using XML wrongly. For example, in XML:

     <myroot> 
     	<thing>
     		<name>Robot</name>
     		<size>15</size>
     	</thing>
     	<person>
     		<name>John Smith</name>
     		<id>12345</id>
     	</person> 
     </myroot>

And:

     <myroot>
     	<person>
     		<name>John Smith</name>
     		<id>12345</id>
     	</person> 
     	<thing>
     		<name>Robot</name>
     		<size>15</size>
     	</thing>
     </myroot>

These two XML documents produce identical DOM and or XPaths. The fact that person and thing are inverted in the second example is irrelevant, but now try to write a schema definition which supports either thing/person or person/thing ordering.

It is possible to do with just one node switch in the above example, but convoluted. As you add more and more nodes the definition becomes unmanageable, imagine 10+ nodes on the same "level" but they can be ordered randomly, and are all required (and your schema needs to check they exist).

XML schema sucks, really sucks, when you use XML correctly and ignore node order. So if you choose to use a schema you're then forced to also require everything in an exacting order which can be problematic when XML is automatically generated from dozens of different systems or people.

XML schema sucked so bad we wrote our own replacement in Java. It just generates an XML DOM tree (via the standard libraries), then it parses your "schema" file which is just a list of XPaths with either a required, optional, or excluded flag. It is like 20 lines of code and it is better than XML Schema language.