It would be nice for people visiting a wiki entry to also get a list of possibly interesting discussion threads about the same topic.

Xenforo Enhanced Search provides such a widget for threads, but it doesn't work on wiki pages.. There are also some other addons that do similar things for Xenforo without the enhanced search.

It would be nice if the widget could utilize the XFES to find matching threads discusing things related to the wiki page.

If that is too complex a simpler solution could be to query threads that are tagged with the same tag as the wiki entry..
(Although requiring a bit more moderating work to tag each page with a tagname matching the wiki entry, and also having to tag threads accordingly.)

This widget would be a nice way to increase the "time-on-site" metrics that are a ranking factor with SEO, and also increase the potential of a visitor becoming a forum member to discuss and ask questions on the topics