Hi Bruce,
I thought you did a great job of explaining sketchnoting, and I agree that we can make original sketches. Extremely personalized images and text maximize learning effectiveness and are less likely to be forgotten. The Segmenting Principle, I think, applies here the best. When a multimedia message is delivered in user-paced segments as opposed to one continuous piece, people learn more effectively (Mayer, 2009). However, I am not sure if the Modality principle applies in this case. It seems paradoxical.
References
Mayer, R. E. (2009). Multimedia learning (2nd ed.). Cambridge, England: Cambridge University Press.