Water, earth and air

[Rafal]

But how many people, even educated ones, would be able to describe a coat of arms verbally, by separating it into its devices and identifying the discrete type of each?  Specifically, distinguishing whether a sinuous line was wavy, nebuly, engrailed, or invacted?

I would agree. Theoretical heraldry is an incredibly complicated stuff.

You have a lot of concepts and strange words describing different parts of coats of arms. You have a lot of symbolism and tradition connected to each part and its variants. And you have a lot of rules and taboos what must be done, what can be done and what cannot be done. These rules apply to shapes, combinations of elements and its colors and so on.

And different countries have different names, concepts and rules. There is no universal heraldry.
And yet from time to time, someone broke these rules and created something different. In such way he created another exception and yet another rule  

So an average educated man probably recognised most important coats of arms and had some deeper knowledge of his own coat of arms (if he had one) but that's all. You would have to be a "heraldry nerd" to notice the details and know the theory.