Regarding hiding, the only thing that I've ever seen in a forum is a toggle on each section (of topics/forums) that would minimize it to just the topic/forum title. I am not sure this is built-in to Xenforo and not enabled, or if it would require something (plugin) added. However, as for linking more directly to area(s) of interest, if each forum category/group had a link effect which would open a page to view only its constituent parts, then that could be another way to satisfy a desire to limit "clutter" and/or unwanted portions.
If it were done some other way, if even possible, it would have to interact with cookies in the same way that a chosen theme is kept. I would expect that even if it would be made possible in some way to hide any of various sections in a personal config setting sort of way, that some sections/forums would be exempt- such as Announcements and any forums created after the config is set.
