I'd like to point to LaTeX as a viable and useful output format. Among other things, this would allow people to build their own PDFs (via PDFLaTeX) that look a lot prettier than anything XSL-FO can currently do, and it would be useful for people who want to use Confluence as an authoring platform. Ideally, the macro-like nature of Confluence would make it relatively simple to concoct a mapping, e.g.:

...

--> \begin