Phill,
In answer to your original question, I think the most important thing is developing class loyalty. I don't know about other countries, but in the United States I haven't seen much of that in catamarans except for the Hobie 16 Class and the Shark Class (which just held its 44th annual National Championship and has two and three generations of families sailing Sharks).

When you find that kind of loyalty, and bonding among the people who love a certain class of boat, it is a beautiful thing.

But that, again, begs the question of how to build a successful class and keep it together. How do you create "class loyalty"?

And, then, of course, there is also the question of what constitutes a "Successful" class -- is it numbers, or is it longevity?