I took an initial quick read, and it looks pretty good to me. One nitpicky point: you frequently say things like "XML is a document", where you should say "XML is a document syntax" (but it was obvious in context what was meant).
Two points I would make:
Pro: XML is easily internationalized: This is dangerous. I interact with developers all of the time who think XML handles all of this automatically, but naively write XML to (or read XML from) a stream using a platform default character encoding. XML is based on Unicode, but programmers work with XML using programming languages, often without understanding how to properly deal with character encoding issues in their programming language. Developers need to understand that if they handle IO themselves in code, they need to take care to handle character encoding properly.
Con: XML is a space, processor, and bandwidth hog: You mention that "there are an emerging set of technologies that compress the XML into a binary format for transmission across the wire". The HTTP spec already supports transport-level compression using standard compression formats (such as gzip). Few people implement it, though. Maybe you can help enlighten them. :-) In my experience, I've routinely seen compression rates of about 85-90% using gzip on XML. In some cases, I've seen compression as high as 95%. I don't see the need to reinvent the wheel on this one, unless they are looking at other transport protocols that don't support compression.