The problem is that the "shift" in usage has created nothing but confusion. Fandom embraces a thousand myths about what canon is and how it works. I've encountered people who genuinely believe that there's some guy at a desk at Paramount/CBS whose entire job is to apply some official stamp of "CANON" to something before it qualifies as genuine Star Trek, and are startled to learn that there is no such thing, that the word is merely descriptive rather than proscriptive.
And then there are the fans who have become so preoccupied with the question of whether the label should be attached to one work or another that they forget that the really important question is whether the story is good and enjoyable. The people who seem to forget that this is fiction, who are preoccupied with what parts of a made-up universe are "real" and denounce anything outside that as if it were heresy or fraud rather than just an alternative take on an imaginary concept.
Words changing is fine. But if a word is used as a bludgeon or believed to mean something totally unreal and delusional, then that's not healthy. Fans have attached so much toxic baggage to the concept of "canon" that the label merely gets in the way of any meaningful discussion of fiction. A word that changes in a harmful or misleading way is a problem.
What we need to do is demystify the word, get over the myth that it's some kind of value judgment or official seal of approval. Let it go back to being what it was supposed to be, just a metaphor for describing something about stories. Then there'd be no harm in letting its usage shift.
