I'm stuck in a circular loop on this one. I've been thinking about it and have got some preliminary ideas on how I'd do it. Just making a wing isn't the problem. Making one without ruining my Mothing is the difficult bit and I agree with Andrew's thoughts on this (see the M2 forum).
I want to go down the club, put my boat together and go sailing. I can do this in 15 minutes. I don't need help to make sure I get the rig up without damaging it. I dont need safe storage in the boat park for said rig as my mast is in 2 pieces under my cover along with my sail and boom. I don't have to worry about getting sand in the moving parts. I don't need a box trailer or van to take it to events as the boat goes on the roof.
The moth has a good track record of not managing development and letting things happen. The single biggest problem with that attitude this time around is that we have so much more to lose than before. Foils transformed the class - it's still ascending now and I can't see wings improving things rather destroying what's been built. The non circuit Mothies I have spoken to believe it's a step too far and it would stop them from joining in. That is a bad thing.
I personally think that a couple of year hold on using hard sails in competition would be the way forward as it would allow things to develop on the side and give the Moth the chance to grow and re-evaluate when more facts are present.
A seperate note:
Are they legal as it stands? A mainsail has to be held by it's luff to a mast as best as I can tell from the ISAF equipment rules which a separated split flap would go against.
My former class had a fairly simple restriction on the sail - it needed to be able to be rolled/folded without damage.