@J12t Honestly?

I'm going to keep repeating dret's point: https://dret.typepad.com/dretblog/2015/02/json-or-rdf-just-decide.html

We need a metamodel.

We need a way of:

1. Describing extensions (and in the case of AP… core features, like "what the heck is a user")
2. Handshaking on what extensions are supported.
3. Saying what to do if an extension is not supported.

It's too easy right now to write something that is incompatible with the universe but that strictly follows the spec. Compare with, say, the situation with HTTP.