@newt email is pretty nice, just most providers give their best to make it suck.
@newt well, smtp is for transfering mail. everything else is just remote control of mailboxes :) (regarding jmap: that looks like some web frontend devs thought "i can do mail, but better because json" ;)
so.. the problem is that someone you want to send an email to has a mailbox at a shitty provider. smtp is working perfectly fine. don't kill the messenger :D