I just found this article on how the new Fantastic Beast movies, the book/play Cursed Child, and - of course - Pottermore are having an effect on fandom.
I found it pretty interesting (even though I just skimmed over it, I admit). But I also think our nook of fandom found a pretty good way to deal with all new additions to the Potter-verse: After all, anything new or anything past DH isn't really considered canon.
Be aware that there are some minor spoilers for the movie and the play in there.
Love to hear your opinion on this!