Don' see how changing the sails is going to do anything except increase costs for owners. I believe the boat was originally a 1D class. Changing an existing sail design to keep up with an established rating number is backwards. The rating number should be changed.
As a class there is no way the Nacra 20 class will get other cat classes rating changed, so the Nacra 20 class should go about getting the Portsmouth number bumped up using all the exisitng data showing how the developing classes and newer classes are faster than what the current numbers show.
A successful 1D class builds on members, and resale of existing boats to build fleets in regions. Making this older boat more costly to own to race in Portsmouth just seems silly. IF people want to own a boat where the sail race is just as seemingly important as sailing the boat, those people will be drawn to classes just like that. If people want to race an older boat in 1D then they will move towards that class.
As a class we should build on our strenghts and our 1D philosophy, not try to chase other boats.