I agree with the article. In fact, my article on slide design tells you pretty much the same.
One additional point: Use only one font. Maybe two if you can justify it.
I like your article, although the left-alignment in its CSS seems strange to me because the text is all collapsed to the left 50% of the page (for me).
I would recommend reading Tufte as well. Fantastic, pleasurable books to read, as well as educational.