"There's a growing consensus among cryptography engineers (by no means all of them, but a pretty significant set of them) that cryptographic agility in protocols is a design mistake."

And yet in 2018 we have proposals like this: https://tools.ietf.org/html/draft-ietf-ntp-using-nts-for-ntp...

To me it looks enormously over engineered with options, versions and flexibility everywhere.