Hey, Sebastien
It's not a bad idea, but mailing lists are really more...personal, maybe?....than other settings that can be propagated as domain defaults. That's why we didn't make those particular settings part of the domain defaults for mailing lists.
I'll run it up the flagpole, however, and see what we land on. If others want this type of granularity, that would certainly help.
Derek Curtis
COO
SmarterTools Inc.
www.smartertools.com