Currently this extension lists pages sorted alphaberically, if there is lots of pages in a wikiproject then they may want to sort them by date or the assessment class instead. People may want to specify a range of dates or a range of classes or a range of importances. I think it would be nice to add these options to the search.
Sorting by date would be difficult since the table doesn't currently store the timestamp, only the revision ID of the page at the point of assessment. Even if you forced the user to limit it to a single WikiProject, WikiProject Biography has over 1.7 million pages assigned to it, so it would likely timeout without denormalizing the timestamp data into the page_assessments table. Sorting by class or importance would probably be more doable, but only when limited to a single WikiProject.