Hi Darryn,
Ok, I understand why there may be resistance or why it appears that the spinnaker is not that useful in racing if you guys are still sailing the original olympic course. Circumstances which may not be apparent to others like this make it difficult for us to understand why you WOULDN`T want a spinnaker. Now it makes a bit more sense to me.
In SA (the other one ) we haven`t sailed triangles since 1999, not because of the spinnaker, I believe there is an international trend that moved away from this course based on the new olympic course which also did away with the triangle. I may be wrong here, since I live at the bottom of the world. When sailing Dart 18`s we only used the triangle at the Worlds, and then it was loop, triangle, loop, so only 2 reaching legs in a 8 leg race. Even with such a course it is worthwhile carrying a spinnaker, and sometimes the wind switches a few degrees, meaning that one leg is a tight reach, and the other is free enough to fly the kite unless it is really windy. We sailed the traditional course (triangle loop triangle) a while back at the request of the Hobie 16`s who we shared a course with, and still carried the kite on both reaching legs in 12-15knots - you just have to get out on the wire (while non-spin boats are sitting forward and going slowly).
I believe the trend of catamaran classes to sail loops only as opposed to triangles has come about because, even without the spinnaker, a triangle with two reaches in it leaves very little tactical sailing, all you can do is go high early, everyone is chasing gusts and sailing high, luffing eachother up, and then they all end up running to the mark for the last 200metres. With loops only, the downwind becomes tactical, gybing on shifts and selecting the right side of the course can lose or gain you several places.
It`s not that I`m against triangle courses or fast reaching, just that it does not really lend itself to tactical sailing as much as windward & return courses. As far as I`m aware only the Hobie 16`s in SA still do triangles.

Steve