1. All media types are 'document centric.' And real REST APIs serve up documents. So seems fine to me. Also, IANA does not have a 'api+json' type registered (until I did so last night), so the name isn't taken.

2. If you're transitioning _to_ this kind from some sort of older kind. Remember, this is extracted from real, working software; it's not some sort of thing we imagined up. Not everyone is super on the hypermedia bandwagon yet, and some will need to transition kind of slowly.

3. I filed for 'appplication/vnd.api+json' yesterday, and so we'll be changing the document as soon as the IANA gets back to me.

4. You could, in theory. Allowing PUT seems fine, it just doesn't often seem to be the case, so we didn't include it. I wouldn't mind having that in there.

5. You should be, this is an oversight.

6. That's very possible.