Security. I recall a possibly apocryphal story about TCP - namely that it was originally meant to be encrypted. Supposedly it was the NSA who had gentle words

Security. I recall a possibly apocryphal story about TCP - namely that it was originally meant to be encrypted. Supposedly it was the NSA who had gentle words with implementors which led to the spec not including any mechanisms for encrypted connections. So, encrypted by default TCP, for a start. DNS should have a much simpler, possibly TOFU model to help with the usability elements. DNSSEC is just a nightmare and confidentiality is nonexistent. Somewhat controversially, I'd ditch IPv6 in favour of a 64bit IPv4.1 - blasphemy, I know, but the ROI and rate of adoption for IPv6 don't justify its existence, IMO.