JIRA has great custom fields and workflow capabilities. If these were ported to Confluence, it could grow beyond being a publishing tool and be programmable to take over in a number of corporate/departmental databases. For example, I'm thinking it could be a great knowledge base...

Workflow would allow for pages in a given space to be "approved" before publishing. Actions on steps might be to change the visibility to more people, change approval assignments, etc.

Currently each page has a small handful of visible fields: lastChangedOn, lastChangedBy, title, content, and parentPage. Custom fields could augment this and be used for a number of things:
1) additional search capabilities, i.e. keywords
2) macros - i.e. show the results of a search... makes for a nice home page (I used Traction at a previous job, it was quite good at this part)
3) apply templates – by default, the current template shows the title, lastChangedOn, lastChangedBy, and content. a different template could provide its own content and substitute in the provided variables; the variables themselves could be rich text with their own confluence macros, or could be selected from drop-downs, etc.