At writing novels or creating games? I'm open to evidence of either...

At writing novels. So potentially also at procedural level design.

I'm admittedly skeptical. The AI generated novels I've seen have been bad. Really really bad. It's been a few months, however, so maybe the landscape has evolved faster than I expected.

Is there a source you can recommend for further reading?

Which novels? Did you compare them to novels created by handcrafted algorithms? I guarantee you, what you have read wasn't bad, it was fantastically good, compared to anything a software could have come up with without machine learning. So it seems likely that traditional procedural level generation could also be far outperformed by AI systems.

> procedural methods written by humans

I did not understand what you intended here, but I see what you mean. I totally agree that these are the algorithms to beat.

I'd argue that procedural methods should also include human writing processes, which to date have produced the best output.

I assume the technology will get there eventually.