Way back when, we had far fewer subcategories. However, that made finding things too difficult, and that is when we had far fewer members and far, far fewer posts to worry about. Because of feedback we received about difficulties in navigating the forum, one of the Moderators at the time, Randy, suggested that we break down the existing categories into several. That is when we came up with NY Style, Chicago style, Neapolitan style, etc. I think that was the single best idea we have ever had from an organizational standpoint, and I still feel that way today. It took several of us (Steve and the Moderators) several days to move threads and posts around into the new subcategories but I am glad we did it. The organizational format isn't perfect, and there is sometimes unavoidable overlap, and occasionally people will post in the wrong place, but I think it is better than most forums I have visited.
By nature of the forum it will always be a bit difficult, and maybe a lot difficult on occasion, to find what one is looking for. I use the search feature, and particularly the Advance search feature, to find things, although I know that a lot of people for one reason or another do not do that. Some people think that I am some sort of whiz because I am able to find things that were posted before. Part of it is remembering keywords that members used, but most of it is from using the Advance search feature, which I use several times a day. That doesn't always work for other members, especially new members who know very little about pizza and the terminology, so I am always happy to help people find things when they couldn't after using the search feature. Of course, I would prefer that they use the search features before posting their questions.