Reveal.js
Markdown could actually be a disadvantage, since WikiEducator authors are familiar with wikitext.
Wiki authors don't need to write/read markdown. They would just be using the UI. Reveal.js would be storing the content in markdown format in sub-pages.
If it is in Markdown format, it won't render correctly on the subpages.
That's why I said that users won't need to read these subpages. Is there a way we can hide the pages? Or do you know a better way to store this data?
I'm thinking of trying to convert the main page only to a slideshow, but I guess parsing wiki text won't be that easy.
My first suggestion would be to store it in wikitext format the way the prototype does. That might allow additional reuse beyond just the slideshow.
As per your suggestion, I have managed to store text in wiki only using div tags so that it can be read directly as well as used for slideshow and other purposes. Here is a demo I created - http://b.wikieducator.org/User:Aps/SlidesDemo