Dave Paradi had an interesting post this week titled, "Does Great Content Trump Poor Visuals." (Another in my weekly Best of Alltop on Speaking.)
As he told the story of an academic presentation with powerful content but terrible slides, he noted that flashy visuals can't make the case with little content, but wondered if the reverse was true. I'd say neither.
You need connection. With dull visuals, with reading a speech, with no substance - you will have no connection. And no impact. Boredom, disinterest and tuneout. Twitter time for the audience.
Only if the audience is interested solely in the content and not the person and the experience (like college kids listening to a lecture for a test) does content reign supreme. At conferences and in business settings I've seen that happen only once in over 20 years - at a Pharmacist Convention during a research presentation (that would have been best presented in writing anyway.)
To make an impact you need connection, and that's people connection, emotional connection and action connection. It comes from high energy, use of stories (SHARPS), knowing your audience and relating, looking, moving and having a beginning, middle and end, etc. You can have a connection with no visuals, (if you have to), but you can't have a connection with boring and flat content and slides and behavior. If you have brilliant content but don't feel it needs connection, submit a paper. The written medium is faster anyway (just not as powerful.)
Dave said it well when he said to NOT go to the PowerPoints first:
"Next time you start to develop a presentation, don't sit down at your
computer. Go to a quiet place with a pen and paper and allow yourself
the time to concentrate on your desired outcome and the best way to
achieve it. Only after you've got great content should you look to
create persuasive visuals."
And if you're smart, then you will add some great visual ideas from Presentation Zen or Slide:ology.