Many of us seem to be using outliner as a database. I personally do:
Everything I write goes into one outliner document, with no columns.
When I write something new I go through copying related work to my new work area.
I then review what I have.
Brainstorm new areas.
I then separate out the bits I want in my new work from the copied leaving the remainder together.
Write the new sections I want.
I then start organising the information.
Editing until I am happy then I copy into word for grammar checking and then my final publishing program.
My dislikes are mainly concerned with it's failings in following areas they include:
The fixed number of columns (single data format)
Lack of permission flexibility (can always read, write, edit, create and delete whole document), perhaps slit panes left and right one for reading copying the other for editing.
Single view method (the order it is in) I would like to be able to store views (parts of the document that are collapsed or expanded).
create other hierarchies. The ability to create a different index often appeals you could have a master document from which different versions are automatically created for different users.
I often what items in multiple places. Perhaps the hyper links are the answer but they come with problems, bidirectional links or hard links would work better.
Lack of revision control.
Limited to single user access.
Lack of search options.
Hard-links, RC, multi-user would likely require a switch to a file-format more closely resembling a database or file system.
Charles