I'm still studying OCLC's new report: Online Catalogs: What Users and Librarians Want. I don't like their negative take on subject headings (page 52). Especially when the users in the survey ranked "more subject information" above "add summaries/abstracts" and "add table of contents." I would read that to mean that users find controlled subject vocabularies helpful.
But that aside, one of the issue the report highlights that seems to be a neglected area among catalogers is web usability. Usability is discussed on pages 50-51 of the report. Both web usability and information architecture are two new areas of study that we can learn a lot from as we rework how we catalog and create metadata for our users. Glad the report points that out!