Add two commands that cycles a heading (like that in Org mode) in outline-mode:

- outline-cycle: cycles between “hide all”, “sub headings” and “show all” state. They are called “FOLDED”, “CHILDREN”, “SUBTREE” in Org mode. 
- outline-cycle-buffer: cycles between “only top level headings”, “all headings”, “show all” states

Could this be useful?

Yuan