"What is the problem with PowerPoint? And how can we improve our presentations?"
This seems to imply that the opposite assumption you seem to be making -- slides can never effectively transmit information -- is also flawed.
That doesn't mean slideware HAS to be used that way. Steve Jobs tends to do quite well with it. Tufte himself uses PowerPoint for his conferences. I imagine he'd agree with most of what was said in the article. Keep it clean and visual, as a way of cueing the audience with mental images and (extremely sparingly) emphasizing the keyest of key points with text. It should be a springboard for the presentation and not the presentation itself.
Don't throw the baby out with the bath water- these programs were created and has become so popular because they do something people want, and they're the best tools people have, even if they are wielded clumsily.