Mark,
Having been the listening post for many having strong opinions on this over the past few years, my opinion is that it personally doesn't matter to me. That being said, I do not want to force a change that will not be received well by the majority of the class because of the perception that in order to be competitive at One Design, you have to go out and buy a more expensive sail. The
J/30 Class OD rules are established to make racing affordable without having the newest technology.
If a majority of people feel that main sails with unrestricted material are affordable and offer longevity - I'm ok with that.
So - my opinion since I have no strong sentiment one way or the other... either approach is ok.
ps - Nemesis does very well with a (very) old Dacron main... for what it's worth.....