What. Does that imply the preference of redesign to revision in IETF ?
No.
"If it ain't broke, don't fix it" is a colloquial saying meaning
"Do not embark on repairs of things that do not need repair". It
means "Don't repair a non-broken window". "Don't repair a working lamp".
"Don't fix software that's already working correctly".
it is also understood to refer to systems so complex that often even
their creators dont understand how they work, so that people are
afraid to alter them while they appear to be working, in case
they stop doing so.
the internet is just such a system, although i would say that e=mail
is one of the parts probably best udnerstood (not by me, but i have
met people who seem to get it:-)
cheers
jon