Re: Too much is getting grafted onto the existing protocol
"There's so many little pieces, with spotty support. We need a fresh start where everything is mandatory, with a new MXX record in secure/encrypted DNS (can't use it with standard DNS) that includes certificates etc. to fully handle the "prove your domain is who it claims"."
What's to stop the domains themselves from being hijacked to provide a platform? Plus what if your DNS is spotty?
"It would use a different protocol than SMTP - might be something very similar like XRECV or whatever so you don't need to rewrite from scratch, but it is important that it can't be used with old clients."
It MUST work with old clients because many have no choice in clients. It's old clients or bust.
"The mail server would have a new daemon that basically acted as a directory service to get the public key of a sender/receiver for validation/decryption. The keys would be good for a short period of time like a week/month, and automatically re-fetched when needed or regenerated when yours expired."
And if Murphy strikes on the server, as it's sure to happen? Say goodbye to the e-mail which you already received.
"Two factor authentication would be mandatory. Everyone has a smartphone now,"
Not necessarily. Many people are stuck with dumb phones, or no phone at all by design, saying if they want to be reached at work, they'll bloody be at work. Plus phones get lost or stolen.
"and hopefully people with the new clients could help evangelize the laggards into conforming."
And if they DON'T because the laggards also happen to be over their heads?