I think the fact that Zodiac wanted to communicate with authorities and the media tells you much more about the kind of person he was than the ciphers could.
A big problem with ciphers is that the more complex they are, the more likely the message will get scrambled in the encoding. An incompetent cipher is more secure than the best encryption methods; nobody can read it.
They should study this. It should be pretty cheap since you only need to study one person from each era to draw conclusions about whole generations. This is how science and reason work. π