We are way past the point where backwards compatibility is an
acceptable excuse for something like this.
I'm curious if somebody can produce an example, where NO-WS-CTL
is actually needed in "domain literals" of an existing network
using SMTP and/or the Internet Message format. At the moment I
still think that it's not even "backwards compatible", it's a
hypothetical "IPvFuture" construct incompatible with RFC 3986.
if common sense isn't enough here, how about the fact that it
is pretty clear that these things have obvious and severe
interoperability problems that will make it hard to meet the
criterua for draft standard?