Michael Alley describes an "Assertion-Evidence" structure for slides, in which the heading becomes something more like a sentence that states the point, and the rest of the slide presents evidence in support of that. http://www.writing.engr.psu.edu/slides.html

This approach tends to do away with traditional headings altogether, so it tends to push you in the same direction as, or even a step beyond, the production-oriented advice given here.