Problem: Currently, a category page includes a list of pages, with no extra information. The list is ordered by category tag.
The subcategories have an arrow icon to show its subcategories. However, the supracategories don't have that option.
Also, the pages of the subcategories are not directly accessible.
I think that category pages should have more options to make them even more useful.
Who would benefit: Editors and readers alike.
Proposed solution:The page list should have a "Show pages of subcategories" option.
The page list should be sortable by both category tag and page name.
The page list should have an "More information" option. When active, each page in the list also show the first edit date, last edit date, file size, number of editions, and additional buttons for "Edit page", "View history" and "What links here". The list should be sortable by category tag, page name, file size, first edit date, last edit date, and number of editions.
The supracategories list should have the same format as the subcategories list, with an arrow icon to show its supracategories.
Sorting by page name would be an expensive operation, without database changes to denormalize the schema (which is unlikely). As with your other proposal, fetching the first edit date and number of revisions would also be expensive, as would sorting by any of the things you subsequently propose. Anomie (talk) 14:40, 21 November 2017 (UTC)
Sorting can be done client-side. The server only needs to send the data with any default sorting. --18.104.22.168 17:42, 21 November 2017 (UTC)
People would consider it a bug that when they hit "sort by size" it sorts only the 200 already-shown entries instead of bringing in the larger entries from later in the default ordering. Anomie (talk) 14:55, 22 November 2017 (UTC)
Selecting the current page with 200 items could also be done on client side. --NaBUru38 (talk) 19:19, 22 November 2017 (UTC)
Sending all 2,000,000 pages to the client so it can select the 200 it wants makes no sense at all. Anomie (talk) 14:44, 27 November 2017 (UTC)
Now you're back to the inability to effectively sort by size on the server. Anomie (talk) 14:55, 28 November 2017 (UTC)
Personally, I think there comes a point when having in-page expansion of data becomes overwhelming. I think viewing pages of subcategories and navigating parent categories are both probably at that point and it's likely a better UI to just click through to the new page. Anomie (talk) 14:40, 21 November 2017 (UTC)