Wheel isn't just another bike components. There are so many different kind. It seems like new ones coming out on the market everyday. It's the first thing people look into when they start thinking about upgrading. Isn't it about time creating a special section for wheels?
But then again we'd end up having a new forum for every type of riding then every type of component in that riding... :/
Wheels are different from other components in a way that you can find many guys that custom build it for you, or you can build it your own. While you can't with other components like brake caliper or bottom bracket. It's nice to have at least minimum knowledge when you order one custom built.