The irony is that the I* rationale for moving NAT-PT to historic
was "to restore the end-to-end transparency of the Internet"


===> John,

With all due respect, I will recommend you to read 4966, reasons to move NAT-PT to historical

Abstract

   This document discusses issues with the specific form of IPv6-IPv4
   protocol translation mechanism implemented by the Network Address
   Translator - Protocol Translator (NAT-PT) defined in RFC 2766.  These
   issues are sufficiently serious that recommending RFC 2766 as a
   general purpose transition mechanism is no longer desirable, and this
   document recommends that the IETF should reclassify RFC 2766 from
   Proposed Standard to Historic status.

 - Alain.