Related to another point you made here, both Tinderbox and FoldingText provide a menu item / keyboard shortcut that unfocuses the outline one level at a time. This is very useful; I much prefer it to OmniOutliner’s behavior, which is to bring you back all the way to the top of the outline.
So, I second the request for either:
a similar clickable path / breadcrumb bar, or
a keyboard shortcut to unfocus the outline one level at a time
(Of these two options, I’d actually prefer the latter. It also seems it might be easier to implement.)
The clickable path/breadcrumb bar is the more useful of the two, IMHO because it orients you to where you are in the outline. If I’m drilled down into the outline, I may get a little lost. That’s why you need a trail of breadcrumbs. ;-)
Meanwhile, though it’s not clickable, I just use this:
--adapted from https://discourse-test.omnigroup.com/t/breadcrumbs-to-know-where-i-am/6326/3
set shortLen to 30 -- length of excerpt for long text
tell application "OmniOutliner"'s front document
set selRow to selected rows's item 1
set selName to selRow's name
if length < shortLen then
set shortName to it
set shortName to its text 1 thru shortLen & " ..."
set crumbTrail to ""
repeat with i in selRow's ancestors
set crumbTrail to i's name & " –-> " & crumbTrail
display dialog crumbTrail & shortName buttons "Ok"
Copy-paste into Script Editor and make sure Script Editor.app is enabled System Preferences > Security & Privacy > Privacy > Accessibility. I’ve put in my Script Menu so I just make a menu choice rather than having to open Script Editor. Could also attach a keyboard shortcut.