WordPress Extend is becoming very popular among plugin authors. I think a sorting feature is necessary in order to help finding plugins easier.
The sort options could be based on rating, popularity, and date added.
I also would like to see RSS feeds for the individual plugins. Users can subscribe to their favorite WordPress plugins and be alerted when there is a release. Having RSS theoretically could also aid in detecting (from the WP dashboard) if a newer release of a plugin is available on WP Extend.