What functionality is missing? What is unsatisfying with the current situation?

Article previews/mouseover snippets are a great tool, especially for allowing site viewers to reference or preview articles without actually having to click into them, and the table of content widgets are great in their own right for the ability to have an auto-updating list of category contents to place within articles, but the two features don't work together. Article links in a table of contents widget don't give article previews or mouseover snippets, requiring users to manually add the links using the article mention system, and more importantly, manually update those lists as more articles are added to a category.  

How does this feature request address the current situation?

If article previews and mouseover snippets worked on links provided by table of contents widgets, or if there were a setting to enable them, we could have the best of both worlds, with auto-updating article lists that viewers can preview with just a mouseover, rather than having to click into the page.