The thing is, with too many subforums, each will only have a thread or two each. With too few, we'll have the same situation we have now. We'll also have people bickering about the way they were subdivided.
I also just checked out the "Cool Places to Fly" subforums. With the exception of Airventure, there are not very many threads per subforum. We eliminated all the podcast forums because they were unused except for being spam magnets. No one noticed or cared enough to comment.
Just to let you know, though, this issue is under discussion by the MC.