I am SO qualified for this. Actually, I'm probably at well over 2500 hours on powerpoint. And I agree it sucks for communicating complex ideas.
The problem is most managers don't want to hear the complex ideas. I used write reports describing methods and results. Nobody read them. Then I wound up doing so much powerpoint that I once went over a year without writing a real paragraph. Took some work to get my prose skills back when I needed to do a white paper. That's part of why I'm on LJ--it keeps my writing in practice.
Hat tip to sappersgt.