The question in my mind is "will the industry REALLY accept it as a Standard?" I have no idea ... We as a community need to figure out:
- Can the spec can be implemented by those not closely involved in its creation? (for example, there are significant bits in the first incarnation of XML 1.0 that assumed a knowledge of SGML; will the ability to implement the XSD spec depend on shared knowledge that it not written down in the spec itself?)
- Are implementations interoperable in practice? We need something like the OASIS XML test suite, and someone to do for XSD what David Brownell did for XML to rigorously analyze the degree to which different implementations of the spec yield the same results from the same inputs.
- Where is the "sweet spot" for ordinary users? In other words, what is the "Common XSD" subset that ordinary users can easily understand AND all the implementations handle properly?
- What's the real business case for selling XSD to non-geeks? XSD MAY add more value to real business systems than it costs. There is a theoretical case to be made for why a declarative constraint specification language such as XSD is "better" than procedural code that validates business rules ... but can we REALLY use XSD to build practical examples that prove it?
- If XSD can't meet some or all of these criteria, can TREX and/or RELAX do a better job? And if they do, will the CTO's of the world care?