Have yet to go through Evan's post, but as you point out, the equations might be the most accessible way to truly comprehend relationships between 4 or more variables.
However, libraries like Tangle are powerful tools to visualize and understand relationships between 2-3 variables.
Maybe visualize, but understand? Doubtful. I don't think the computational overhead justifies a complex subsystem instead of just something like "x = cos(theta)" without some fancy rotating control.
My take on the best way to write/use such a document would be first present the math, then a reactive example. The user should read the math formulate a hypothesis/visualization/understanding of the system then use the reactive document to verify or falsify the concept.
This does not remove mathematical understanding from the document, but adds an opportunity for quick verification of an understanding. And according to my vague understanding of learning and neural connection getting quick feedback is key to forming strong connections.
However, libraries like Tangle are powerful tools to visualize and understand relationships between 2-3 variables.