Don't think we need to make it lossy - just would need slightly smarter
conversion tools when converting back to XML which know when they have to
put in blank or standard XML fields which have been omitted for simplicity
in other formats.
So the human friendly title is one thing that would be lost with your proposal... and things like frame/block size (unless you're happy to say it will never happen, and I'm wary of doing that, just as I'm wary of telling people to support another specific networking or storage or security or whatever protocol to cover our shortcomings).