Martinet

Clear and unambiguous markup language which allows for styles: ad-hoc editing (defining a look on each instance of a span of text as opposed to style-based editing where one specifies how things should look in a central place) is tedious & error-prone approach that doesn't scale up. But ad-hoc editing strongly favors casual improvement with a very low learning curve.

Easy table of contents editing

Free-form searches

Document inclusion to avoid errors by repetition. Inclusion should never reveal that a portion of a document was included.

Nesting one object (say, a table) into another (say, a list item). This is trivially easy in any mature markup language such as HTML. Newer markup languages are typically a lot less well thought through (Markdown, many wiki markup languages, just about anything inferred from informal notes).

Renaming pages including page references to avoid breaking links: each documentation system will have its own peculiarities about naming. DokuWiki, for instance, keeps all pages in a 2-level hierarchy – namespace/page – and it's likely that each documentation project uses one namespace. Hence Folder ACE count and Print queue ACE count need to be kept separate by naming pages differently. This means that renaming pages is sure to come up during editing.