Don’t create too many initial categories, as you can overwhelm your audience. You can always add more categories, and easily bulk recategorize topics later. It’s better to figure out the organization as you go rather than assuming you’ll get it all right from the beginning (hint: you won’t).
Good points from both of you. Let’s keep it and maybe take it as a sign that we should get more web designers / developers on board. Responsive design, CSS, front-end development and all that is also part of designing in open source.