what i really miss in most (all ?) of these frameworks is an embedded markup language (markdown or variants), so that one does not have to bother with html in order to create lists, fonts, tables etc.
In my own "sttp" tool, most of the javascript is exactly for this purpose - the slide deck is just the content of a textarea and is almost readable even without formatting.
For styles, i use braces and css styles e.g.
{style1 style2 style3,some text}
which has the compactness of latex and the flexibility of css.
And here I am just now getting decent at beamer. :( I wonder if it is possible to compile a beamer presentation to html5 easily. Fun side project, at any rate.
Use Pandoc! It takes normal Markdown and can create a beamer or fancy HTML presentation from it automatically. Or, if the HTML presentation frameworks it supports aren't to your liking, just create a quick template that spits out something compatible with your favorite framework.
https://github.com/hakimel/reveal.js