Joe, it depends on what you mean by "canon," doesn't it?

Religious studies aside, in the liberal arts the "Shakespeare canon" simply meant all the works known to be by Shakespeare. It implied that there might be other "non-canonical" works falsely or questionably attributed to him. Just as there were "non-canonical" (Apocryphal) books of the bible.

Later (maybe in the early '80s) it meant a body of stuff that was officially regarded as "the best." The word was (and is) often used invidiously to suggest that the so-called "canon" is artificially set up by the Powers That Be to exclude stuff they don't like made by people they don't like.

A "classic" may be good, but a "canon" of classics can be arbitrary, artificial, exclusionary, and bad - according to that way of thinking.