It's not being modified BECAUSE of it's olympic status by the ISAF.
That can't be the answer... they fixed the 49ner with multiple fixes in the first and second Olympic cycle. ISAF and Nacra control this class and not the sailors... so the responsibility is really up to them.
You fix things mid-cycle that lead to mechanical failures in the boat because boats breaking under normal sailing condition is a crappy way to lose a race and a really good way to get a bad name for your event. For instance, when your masts are breaking, you build an interim aluminum mast until you can get the carbon one designed and built properly.
You DON'T do a quick fix on things dealing with handling and performance because A) all of the boats are the same and nobody is gaining an advantage over other teams because of it B) it doesn't affect the quality of the racing, and C) making this kind of change resets the training regimen and causes teams a lot of lost time to relearn to sail a boat with different handling characteristics.
Frankly, if the boats are difficult to sail well, it leads to more exciting racing to watch as evidenced by the recent America's Cup.
