This sounds suspiciously like attempting to invent some kind of meta-XML.
To make matters more complex it’s pretty obvious to us that we need to have support for multiple data serializations. At a minimum we think we have to support XML and JSON but following the old computer science rule that there are only three numbers “0, 1 and infinity” this means we will eventually have to support more.
It seems to me that the need for having to support both JSON and XML is not at all obvious, so this looks like starting from a false premise. But then again, Yaron Goland is an extremely smart guy, so maybe I’m missing something.