The biggest example I can refer to is the Tornado class. Over 2/3rds of the members voted against the upgraded Tornado; this would make for a solid base to continue the (classic) Tornado class for years. However; 18 months later the classic Tornado was all but dead and the few break-away sailors gethered a whole new class around them that would dominate once more.
1: The class did not want the new rig, but ISAF did..
2: The Tornado will have a carbon mast from 2005.
So, we will soon see if changes kills the Tornado class or if no change would have been for the better

(straying a bit off topic for this thread now, aren't we?)
Regards
Rolf