Paul Smith wrote:
*Now* is the time to do this. If the IPv6 mail standard is finalised
allowing fallback to AAAA, then the cat is out of the bag, and there's
no going back.
The above seems to nicely capture the problem we are having in this dialogue.
Some folks are treating IPv6 considerations in isolation and even as a
clean-slate approach. Others are attending to the larger, installed system and
viewing v6 issues as an incremental change.
This is a pretty classic tradeoff between the pragmatic vs. the ideal.