This is just me being the "ideas guy" (i.e. not thinking on feasibility, just cool factor), but:

The wikis would federate themselves roughly like Lemmy instances do: you can register on one and edit/comment articles on another, you can easily link articles cross-wiki, things like this.

If you browse the wiki through Lemmy, the wiki looks like a community in its own instance. Each article is viewed as if it was a Lemmy post, except that you can edit everyone else's OP (as wikis are collab). You can even post on it through Lemmy, but it's only text posts, and they'll get "translated" into wiki articles. If you comment on a post=article, it starts a discussion page for that article.

From the wiki's PoV, each Lemmy community is simply a federated wiki. You can even link them as such.

A few controls would need to be in place, specially from the wiki PoV, to prevent abuse. But I think that this would make both sides more useful. And while I've been focusing on Lemmy, I believe that a system like this can (and should) be extended to Kbin and Mastodon.