As many commented on the "" theme, tools don't create bad presentations, people do--even if the tools must share some of the blame for encouraging certain paths.
But, as a reader points out, we shouldn't just blame software in this regard:
It's just too hard and time consuming to freely draw diagrams and text, as on a whiteboard. Maybe this issue will finally improve with touch computing, but until then, we do all waste a lot of time...
This is an important and insightful point. We mostly use keyboards and mice to enter information into our computers. The keyboard is still similar to that of the first commercial typewriter sold by Remington, beginning in 1873. Even the mouse is nearly 50 years old.
With a keyboard and mouse, some things are natural and straightforward. Keyboards are obviously about entering sequential letters and numbers. Mice are optimized for tasks like selecting things, inserting standardized objects, and moving them around in a two-dimensional space.
Others aren't so natural--no matter how cleverly designed the software. While experienced designers can certainly construct complex images using a keyboard and mouse, quick napkin sketches, decision trees, informal charts, and so forth are far harder to create. The keyboard and mouse, as abetted by the software designed to be used with them, make it relatively easy to produce certain forms of polished professional content while discouraging forms that we routinely use to communicate absent such mechanical constraints.
Any number of other input devices have appeared over the years of course. Joysticks and game controllers are commonplace, but they're more about navigating through three-dimension space (and shooting anything that moves) than they are about creating. Tablets have probably come closest to providing a way to casually sketch. But tablets are surprisingly unnatural for most people because the surface you're drawing on isn't the surface where the output is displayed.
Screens on which you can draw can map far more directly to the physical world. Specialized examples of such screens aimed at graphics professionals are expensive today. But as multitouch displays become commonplace and even routine, it seems likely to me that they'll gain the critical mass to encourage presentation software that's optimized for them.
Polished graphics will still take time and work, of course. And perfecting the look of a major event keynote will require the work of professional designers. But we can hope that for routine day-to-day needs--whether presentations or long distance collaboration--the quick-and-dirty sketch will replace some professional-looking but ineffective bullet points.