Some sort of memories-style file for topics so it can generate even more cross-references and a sort of shared world. Not for total coherence; the natural contradictions the LLM is going to generate anyhow is just part of the charm. But still sliding the scale a bit more in the direction of coherence that the "use this page's context when generating the clicked link" already leans would add some more appeal, I think.

For instance, you can build memories around times, topics, and people, so maybe specific individuals will be quoted multiple times over the course of the wiki and could build up a specific identity within the shared world.

Also... I don't know how you are thinking of this internally, but other than the issues of token spend and the $$$ involved, I would say, don't even blink at simply nuking the site at some point and starting over once you have some moderation stuff in place and other limits. Don't put it on yourself to filter out what garbage has already been generated. It's all transient content. It lazily regenerates itself anyhow. It's not precious, except for, like I said, the aforementioned token costs, which I don't deny. You can probably put some other tweaks in to the prompt to your liking at that point too.

Many LLMs are surprisingly good at using specific named authors (rather than just example texts) to evoke a style, so you could try "in the style of Jorge Luis Borges" or "…Douglas Adams" or "…Robert Anton Wilson" – whose surreal/absurd/fantastic styles could be fertile seeds.

(If not already familiar with Borges, definitely check out his 'Tlön, Uqbar, Orbis Tertius' and 'Library of Babel' as inspiration.)

While "each article written once" an interesting & useful constraint, a Hallucipedia that evolves like Wikipedia, with revisions "towards" some level of inter-article agreement, or even shows scars from edit wars between competing schools of thought, might also be fun.