Thanks for the feedback. Search(text and geo) are on the list but lower down. Niche job boards tend to have a smaller number of listings, so the need to do lots of filtering/sorting is not as crucial as larger, less focused sites.

You are absolutely right about expired jobs and empty category/geo pages - they can be a real challenge from an SEO perspective. For now we are handling expired listings by hiding them from the site, but keeping their URLs active w/ an expired message. My hunch is this will keep the page rank for a while but we will eventually drop and 301 them to the sites homepage.