Cutting the circle

Max Gadney selected this as one of his best graphics of 2010. I agree it’s good, but yet again, circles are used to indicate relative size – and we know that we can’t visually make circles add up. The Venn diagram use of circles for non-quantifiable items is fine – see the work of Jessica Hagy. Can anyone rethink this following Isotype principles of graphic units that are easily (visually) manipulated by the reader?