Reading through the feature list on Wiki Matrix whilst updating the release number on there revealed a pair of features that would be both (relatively) easy to implement and be rather useful!

This is the other of them: Automatic tables of contents. Perhaps we only show it if there are more than, say, 4 headings in it? It could be configurable, of course. MediaWiki shows it before the first major heading, but after the introductory paragraph(s). Maybe we could do something similar? If we're undecided we can always make that a setting too. Of course, we'll want to be able to turn it off if it's undesirable as well.

This might do well as a part preprocessor in a new module, actually.