Your sugestions look good. I don't think dividing things into too many categories is a good idea, however. As it is, when looking through a forum, there are topics which catch my eye, that I would never have expected, and perhaps would never have come across. The section for beginners is a good idea, as well as the Radio, RC sections, and I like how you have divided the tech section into three parts.
Regards,
Robert
Edit, but perhaps a section on sensors would be helpful?