Going a bit (only a bit) against the "Zen" presentation philosophy, I have argued before that overwhelmingly complex PowerPoint charts could be used in a large keynote presentation, if (big if) they are positioned well.
One way to use it is as follows:
  • Put up the overwhelmingly complex chart, message: "it's complex, don't even try to understand this now"
  • In a subsequent chart, wash out the original object
  • Start highlighting individual components for further explanation
You can use the "paste as PNG" function in PowerPoint to transfer any object (including complex groupings) into a picture and subject it to the regular picture manipulation tools available to you: resize (a pain for complex PowerPoint objects with text in them), crop, and of course re-color.
Recoloring the image with a very light overlay creates a wash out effect that you then can use as a background for subsequent highlights. I have tried to explain all this in the following SlideShare presentation (click on "screen" image at bottom right for full screen mode).

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