thank you for putting this together!
question: do you think multimedia assets could be encoded within a single URI? looking at the use cases, it seems like 1) multiple assets to cycle through, 2) revisions, 3) multi-aspect ratios, etc. could follow a new tokenURI standard that references a list of objects or a list of URIs. of course this flavor of standardization (and adoption) would be more offchain but remove the need for a new ERC-721 standard.