I just finished putting together an annotated list of
potential applications of natural language processing to on-wiki search. There are dozens and dozens of ideas there—including many that are interesting but probably not practical. If you have any additional ideas, questions, suggestions, recommendations, or preferences, please share!—either on the mailing list or on the talk page.
The goal is to narrow it down to one or two things to pursue over the next two to four quarters, along with other projects we are working on.