Page Approval Function
When a user created or edited a page, it wont publish right away, rather have a admin or higher lever user to approve the modification, then publish.
Dropdown Navigation Items
Support for child navigation items to allow dropdowns in the main navigation pane. If you have a large wiki, it can be hard to organize your pages without some type of collapsible navigation.
User Activity Page
It would be nice if users can see newly shared articles on the homepage when they log into the app.
Real-time editing/collaboration (like GDocs)
It might be hard to integrate, but it would be a killer feature that no other wiki offers. Perhaps you could use ShareDB: https://github.com/share/sharedb https://en.wikipedia.org/wiki/Operational_transformation
API / GraphQL Docs Editor
An editor to describe and document APIs (e.g. Swagger, readme.io , etc.) for both REST and GraphQL endpoints. Ability to automatically analyze a GraphQL endpoint using introspection. Ability to automatically analyze REST endpoints using standard formats (such as Swagger).
HTML in titles/descriptions of pages/Hide the headers
I like more customizability in the headers things like mdi/fab/fa icons what is doable with html but not in the headers or just the ability to hide the header for a specific page the header will exist for seo but it won't be visible only in the browse bar or when you search it on google+
Add support for backlinks
Allow a page on the wiki to display which other pages on that wiki are linked to that page.
navigation area default collapsed option
Depending on the window size, the blue navigation area on the left disappears into a round blue button with 3 horizontal white stripes. It would be nice to have the option to always (independent of window size) have the navigation area collapsed. This would maximize screen real estate in some cases