Ecco outlining is as close to WYSIWG as any outliner I've seen and it would be 
GREAT if Writer could eventually incorporate this ability. If so, it would make 
it a MUST-HAVE app for all writers and editors. Below is an extended 
description of its functionality as I remember from a great PIM program 
called "Ecco Pro" a few years back.

Some applications apparently use "outlining" to mean "organizing information
in hierarchies", and use various kinds of presentations and operations
derived from their interpretations of this. In Ecco, an outline can be created,
edited, and viewed as a document in outline form. (In this description,
I'm purposely ignoring the many useful things that can be done with items in
an Ecco outline, in order to focus on this aspect. Also, I focus on the
most common and basic operations on outlines -- the ones that will be "at
your fingertips" when you've gotten some experience with the application.)

The unit of outlining is the "item", which is roughly equivalent to a paragraph 
in a word processing application. It contains rich text, possibly including 
embedded newlines, and can be of indefinite length. The usual tools are 
available for editing text in an item (which is done in place in the outline, 
without losing any visibility to the neighboring items): cut/copy/paste, Ctrl-B 
to make text bold, Ctrl-I for italic, etc. Menu items are available to change 
font, size, style, and color.  All font settings can be made down to the 
character level.

You begin with a blank "notepad", which looks like a sheet of ruled paper.
Click on the first blank line, and a small bullet appears, with the cursor
placed to its right.  After typing the item, you can press Ctrl-Enter to begin 
the next item at the same level (Shift-Enter to embed a newline in the same 
item), Ctrl-R to begin a new item at the next level down, or Ctrl-L to
begin a new item at the next higher level (if the item's not at the top
level).  (You can use these when on any item, to insert a new one after
the current one.)  The outline structure is shown by indentation in the
usual way.

If the currently selected item already has a child, pressing Enter will
insert a new child before it; pressing Ctrl-Enter will insert a new item
at the same level as the current one, after all its children.  (If the
current item doesn't have children, Enter will insert a new item at the same
level.)

Outlines can be collapsed and expanded, either globally (all items at a
given level) or locally (subitems of the currently selected one). Hold
down the Ctrl key while pressing a digit (1 through 9), and all items at that
level and below (in the entire outline) will be hidden.  With an item
selected, hold Ctrl and Shift to get the same effect, but only on that
item's children.  For convenience, Ctrl-H is the same as Ctrl-Shift-1
(hide all descendants), Ctrl-J is the same as Ctrl-Shift-2 (show only
immediate children), and Ctrl-G will expand all descendants of the item.

To move an item up or down a level, use the Alt-LeftArrow and Alt-RightArrow
keys.  Alt-UpArrow and Alt-DownArrow keys move an item up or down with
respect to its siblings at the same level.  (In all these moves, the
children of the item move with it.)  An item can also be moved with the
mouse anywhere in the outline, at any level, by "grabbing" the small
bullet and dragging it.  As the mouse moves, a small indicator will become
visible in each place where the item can be "dropped", to make it clear what the
effect of releasing the mouse button will be.  If several items are selected, 
they can be moved as a unit by grabbing any one of their bullets. To cancel the 
drag operation, return the mouse to the item you started at and release.

As with text, entire items may be deleted, cut, copied, and pasted.  To select 
an item, click to the left of its bullet.  To select several items, click and 
drag, or hold down Shift while pressing the up or down arrow keys.  Also, as 
with most text editors, Ctrl-Shift-End will select all items from the current  
to the last, and Ctrl-Shift-Home from the current to the first.

Items may be split or joined.  To split an item, put the cursor in it at some 
point and press Ctrl-Shift-S; the text after the cursor will become a new item 
just after the current one.  (As with pressing Enter, the new item will become 
the first child of the current one if there's already a child; otherwise it'll 
become the next sibling.)  To join a sequence of items, select them all and 
press Ctrl-Shift-J; their test will be pasted together, separated by spaces, 
and appended to the first item.  (These operations can't be undone.)