The heavy use of "IRI" as terminology in the spec, referencing RFC 3987, raises a number of thorny issues and actually makes JSON-LD out-of-sync with the latest developments at W3C. See https://www.w3.org/International/wiki/IRIStatus. (Also, the status of RFC 3987 has never moved past PROPOSED.)

If the spec continues to use the term, then there should probably be a section added to the spec to explain how JSON-LD proposes to solve the IRI problems such as inconsistent use of punycode and percent encoding. I suspect it would be simpler to use "URL" everywhere, per W3C recommendations, with a simple (foot)note explaining that the intent of "URL" is to encompass internationalization as originally envisioned by the IRI effort, but will track the work of the new URL working group for the particulars.