Hmm. I just cut the plugs to cure my own ignorance and curiosity. The lessons learnt were quite iluminating. When you know what to look for, there are many ways to skin that cat.
In the end, do not forget to examine the piston top, piston bottom and skirts . They all contribute to understanding how well the engine (as a person) feels. I mean, the big picture that is made up of ignition advance, cooling, plug choice, fuel grade, carb tuning, oil type, and oil / fuel mixture.