What, precisely, is wrong with SMTP?
Your issue is with the implementation, not the protocol.
In my opinion, SMTP is as bare-metal as possible (excluding? binary attachments) while still being human readable.
No, I have an issue with SMTP too (might come from working on a mail server all day today). I have an issue with the need for SMTP, LMTP, sockets, IMAP, POP3, and all the various work to get encrypted traffic to run a mail server. Its a friggin mess of unrelated protocols with varying degrees of specification with arcane knowledge required or it bites you (like the article shows).