From the author's website: it uses an algorithm to randomly generate pleasing colour schemes.

This is correct, well investigated!

I'd love to see the example displayed in vimdiff format. Many good looking themes become unusable when vimdiff highlighting is applied.

Seconded. The same thing also applies to folds in vim, and sometimes to gutters and things like NERDTree or ctags scripts. It's really frustrating to have a great theme that in certain edge cases applies black text on a black background or (more commonly) white text on a light gray background.

Can you put the theme permalink in the generated theme files as a comment? Seems like it might be handy to have someday.

Care to share the source?

I've never understood people who use bright green on a black background or anything with that much contrast. It feels polluting to my eyes, like radioactive waste.

High contrast should be reserved for important items. That way they can have higher contrast than the surrounding text and stand out more.

I've seen a few people who program with just flat green on black. No syntax highlighting. I cry a little inside.

How is that different from flat white on black with no syntax highlighting?