I don't need to know any of this.
One commonality that Lewis, Tolkien, Howard and all the early fantasy writers had was that they did not overly explain their magic. Magic just is. For me, if a person begins to read a fantasy novel, then the person has already suspended their disbelief. If a person views The Matrix, then that person has already suspended their disbelief in a number of ways. If a person votes for an established politician, then that person has already suspended their belief in reality.
Anyway, I do not need to know how it works (except for Brandon Sanderson's Mistborn series in which it was essential to the story to explain magic up front).
One tremendous aspect, of Rowling's seven book tale, is how Tom Riddle... and Lily's sacrifice... and Dumbledore's kindness... and Snape's frustrations... and Harry's abilities are all easily traced throughout the series. The only part that seems tacked on last minute is Luna Lovegood. (Nothing for the first four books... and BAM!!! Here's Luna!) So the new explanation of magic seems irrelevant, unnecessary, and poorly timed.