To Dave: If we are going to discuss outliner and structured framemaker, the title of this thread is severely misleading, so perhaps a new thread should be started? However, since structured framemaker is not even in this forum (but in a sister forum), I hesitate to start a new thread here...? Maybe the list mom might move this somewhere?
Anyway, to answer you, here is what I can say:
White space: Yes, too much I think, but I set my Structure View to 80%, and I have customized the font in the ini file to use Arial (which is pretty dense). The balloons are not useless, instead they are very informative of the structure, since they are the names of the elements. You can click on the balloons to show or hide their attributes.
Example: In the document I have open right now (a single-file document), the structure view shows all the 7 topmost elements in the document, with "closed" attributes, and that occupies 47 mm on the screen at 89 ppi. Not too bad I think. Each line has a ballon and the first few words of the content regardless whether the content is a heading, a table of contents, or whatever. Pretty useful, isn't it? Much better than the thing in Word! To see the entire content of that element, just click the element in the structure view, which brings that part of the formated document up in the main view.
Changing the hierarchical view is easy: Click on the +/- sign to see more/less. Shift click it to open close all at that level. Normally, you do NOT have everything open; rather, you focus on the structural level you like.
However, expandability/collapsibility could have been made better by Adobe, but you can use a plug-in from West Street Software 'WS Structure Tools plugin' to radically improve the easy and flexibility with which to expand/collapse.