notes:

type is not polite, it's mandatory. I just made a PR for this

cypherlink is a cryptographic token that refers to another object. hashes, public keys, bitcoin addresses all count as cypherlinks, but message cyphertexts and signatures do not.

Definitely agree on binary formats for cryptographic data (links, signatures, cyphertext)

I think removing the sequence number forces the hand of implementers a bit too hard.

Also, timestamps: The application layer loves timestamps. Everyone is requesting indexes for that. As protocol designers, the application developers are our users, we need to keep them happy if we want people to use our protocols. If you remove the timestamps they'll just add them to the content, anyway, so I don't think you'll win this argument. If someone starts spraying randomly timed messages it will tend to be behave weirdly in applications, and that will have social rammifications.

Anyway, while these might be good ideas, I think it's going too far introduce these all at once. Just rolling out the binary format will be hard enough.