I'm fascinated by this because the criticism of the TWILIGHT books that's caught my attention most strongly is rooted in feminist ideals - Bella's passive, she's complicit, she's subservient, she's an exemplar of destructive tropes about girls and women, she's a weak character who flies in the face of efforts to create female characters who are fully dimensional and real, she surrenders agency in a way that patriarchal forces want girls and women to surrender, etc. - and that by flipping the gender of the characters, Meyer's taking that perception of the female character and inverting it. I don't see that as a minor detail; it feels HUGE to me. Now, I probably won't read the book, as I said, so my perspective on whatever's said about the new book will be limited. Still, I'm curious to see it.
This is my biggest curiosity, because it was one of my biggest criticisms of the books. Not so much THAT the author is swapping roles -- but what happens when she does. I wonder if the male-Bella will have these same characteristics of the original female-Bella, and if so, what will the criticism be of that character, if any? And how will critics view the new female-Edward, the strong, powerful, in-control character? Also, by gender-flipping, is there anything about the books and plot that HAVE to change, and have changed? I don't know. But it's curious. I'm curious. (But probably not enough to read for myself.)
And yes, people expect a lot from successful authors. JK endured a fair share of criticism in her first post-HP attempt. Speaking of JK, I, for one, would totally read a series in which Neville Longbottom gets marked by Voldemort as the Chosen One. Or the series written in Hermione's POV. Or Snape's! A prequel! A sequel! I'm sure fanfic exists for these. But if JK wrote it? I'm pre-purchasing today.
I don't know what motivation an author would have for writing stories that rework original tales, especially popular ones. For themselves, for fans, for money? It's different for each author who does this. After that, it's up to the readers to decide, discuss, and dismiss -- or embrace.
It will be interesting to hear what those (of you) who read it have to say!