Do you think these transport, in the future, should support true
binary?
I don't care.
MIME spec cares.
Or, do you think we should avoid using NULL even with binary just
because there are widespread use of NUL-terminated strings?
No, supporting binary is harder than supporting 7bit or 8bit.
It's no harder.
That is
the purpose of having a distinction between "8bit" and "binary"--the
former is an assertion about the content which permits simplification
in handling.
They merely correspond to SMTP distincitons.
If you drop NULL this time, we will see the argument of "the widespread
use of NUL-terminated strings" again for binary.
I'd say this argument is entirely specious. The entire point of
"binary" is that it explicitly has no restrictions on the permissible
octet values.
And the entire point of 8bit is line-structured 0-255.
It's OK to document that there may be broken implementations, which
is totally different from writing a broken specification.
Specifications which are completely different from widespread
implementation are broken.
Then, because of BSD, all 1 broadcast addresses was broken.
An mere assertion that disallowing NUL in 7bit and 8bit is "broken"
doesn't carry much weight with me.
Then, why do you want to change the spec?
What is the merit?
Masataka Ohta