we should give her adult book a chance before deciding it's going to be awful.

That's true. But it's also true of the works of a huge number of writers who have yet to find that one agent or publisher who is prepared to read their debut manuscript. Even if JKR is being prejudged, she is at least going to get the novel published, because she's JKR.

hasn't been shy about milking it, or about helping to build the phenomenon

Why on earth should she be shy about it?

give everyone the impression that her success is typical

When exactly has she done this? Quote, please. She is not responsible for other people's misconceptions. I cannot think of anyone in the writing business - except for some self-published authors I've encountered on various forums - who actively works to give the impression that success is easy and typical.

she is at least going to get the novel published, because she's JKR.

And that is exactly why I feel sorry for her.

And that is exactly why I feel sorry for her.

She could have chosen to use a pseudonym, precisely to get away from the association with Harry Potter. That, at least, would have given her some control over the way it is perceived by the public (her agent and publisher would have known who it was by, of course, so they would still be making their decisions based on her past saleability).

Does Rowling know you all are talking about her?

Any book should be judged by its content, regardless of the quality of the Harry Potter books any future work of JKR is going to be attacked without thought by some, and praised without reason by others. I suspect the only way to judge will be to read it when it comes out.