Well first of all, there are already a lot of Nacra 6.0s that have added spinnakers. It's not out of a desire to be like the inter20 but because it's a very good strong platform for a spinnaker - it's that simple. The 6.0 and I20 are very different boats and I prefer the 6.0 because it's not quite as high tech, the racing is more "amateur" oriented, and the boat is a little more sturdy.
I have no idea how many active class members there are. In fact, I wonder how important it really is that Performance ratify the changes. Besides having a good nationals, they appear to be a pretty weak organization. The New England folks have already made these changes and are racing (mostly distance races) in this configuration. Rumor has it that Darlene is even working on a specific portsmouth rating for the New England 6.0. I’m probably missing some big point but why is it so important that Performance accept the changes (granted it would be nice to keep everything under one umbrella)?