I find this one of the easier forums to use and navigate.
I don't know what you forum looks like, but I think by using Categories and Forums and have a good flow of structure on the information that helps. Just like good flow of information and structure is important on websites I think the same principal applies to forums.
Some items in the FAQ don't apply to my forum but members have found the information useful, but I also have a "How Do I" forum and some Notes in the Admin. Notices that help the users.
Maybe one of the guru's could make a Mod for you on the having the categories collapsed, but I wouldn't want that as a stock function. Check over at UBBDev,com and see if there is a Mod that would fit or if someone can build one for you. I would be unhappy if I had to click to open each category.