This is always a popular topic.

Matt (wisely) gave the short version of the correct answer. Lots of additional factors come into play, as others have mentioned here.

Design definitely plays a role. Although "real" data is hard to come by, it starts to show up with an increased number of capsizes. For example, H16s can be raced longer in more wind than boats with larger sail plans. They are already more depowered, so can be controlled (by good crews) better in more wind.

The real dilemna is that you cannot make everyone happy. Unless it's blowing 40, SOMEONE will want to race. The OA and RC need to determine if that's the general consensus of the fleet (and this is NOT easy, just ask PU and Means "18.7 Knots" Davis).

Another thing to consider is the level of event (fleet race vs. weekend regatta vs. NAs); although, again, there will be a difference of opinion on what is fair...

Mike