Chart loaded with detail are usually not the best way to convey a message. Except, when your message is that things are actually very busy, complex, interrelated. Then by all means make a busy chart. When presenting, don't feel tempted to go into the detail of its content though, the message stays "things are busy" and [click] you can go on to the next chart.

Art: The Fight Between Carnival and Lent, by Pieter Bruegel the Elder in 1559