Experienced mods moving from Reddit to Lemmy would expect support for integrated wiki pages since it's been a basic feature for so long. They use them for creating directories, tutorials, and all kinds of resources. My sense is that making wikis a separate project on the Fediverse would be too clunky, although I admit it's an interesting idea.

EDIT: They can also be used for bot configs just like AutoMod, which is a separate feature request in itself.