Alright, I’ve read through this whole discussion and I have a few questions. I get that this page’s structure is created by this page, but then you also need an index page for each sub-category as well? The index for this page, must be enormous… or any of the other ones with a ton of articles.
How hard would it be to implement an xwiki style of layout for pages that are part of a Discourse site’s documentation. The UI is simple enough, you check the box on page creation stating that this page is documentation. Now it simply asks you what the parent is. No parent? It’s a top level subject. You set a parent, the page shows up under that subject/category. This completely eliminates the requirement to manually maintain index pages. They look like a lot of extra work that shouldn’t be necessary. And easy to overlook adding things as they’re created.
If you go to https://checkin.technospider.com and disclose some of the items in the sidebar, you can see how the nesting works in a real world example. That entire sidebar is dynamically generated simply by nesting pages under other pages (parent/child relationship). This site only has about 150 pages on it but it would have taken me twice as long to get it completed if I had to make indexes to create all of that.
And that brings me to a UI/UX issue with how the Docs sidebar is laid out. Once you click away from the main page, you lose the initial list of categories. You should have a way to go back on the page somewhere.
Each of your 8 main areas should have disclosure triangles on them so whether you click the box on the main page, or the name in the sidebar, it just drops down and you don’t lose the ability to directly click on another of the main areas.
You have a breadcrumb on each end article, but even that is missing from the 8 categories. Clicking ‘remove filter’ from the subcategories at the top of the page takes me back, but that’s very unintuitive. And you can do some weird things by playing with the filters, for example, the nice green banner disappears if you click ‘no subcategories’