Making EXMH work with NMH is alarmingly simple. Add this to your
*Mops.reply.m.c_replyall: Msg_Reply -group
This will change the command reply-to-all calls.
This doesn't strike me as being particularly burdensome for the EXMH user to
do. It also doesn't strike me as being particularly burdensome for EXMH to
have a switch at install time for the user to specify whether NMH or MH is
being used under the hood, thus allowing EXMH to default correctly.
MH was moribund before Richard began revamping it as NMH. Anyone who insists
that Richard should adhere strictly to MH's ancient ways is simply asking for
a return to that period of moribundity, which IMO benefits no-one.