Ref: the simplify point. The famous (via Tufte) graphic of Napoleon's invasion of Russia (http://www.improving-visualisation.org/vis/id=205) is widely cited as as a great example of conveying information useful and dramatically. If you accept this as an exemplar--you don't have to of course--it's anything but simple. Rather, it's a graphic that requires study but, given that study, offers up a great deal of information in return.