The challenge/goal is to have an entry level sequence that can be flown by a very broad range of pilots with a broad range of planes (including trainers). Masters needs to be challenging enough to differentiate top pilots, and the classes in between need to have reasonable steps in difficulty such that pilots can progress from one class to the next. I'd suggest the ideal step size will never be agreed upon, but in practice, the number of pilots in pattern determines how many classes are viable, and how many steps (classes) there are on the way to Masters. Many local contests are seeing ~20 flyers these days, which means an average of 4 pilots per class (including FAI-F3A). It doesn't make much sense to add another class to have even smaller numbers in each class.

Regards,