No, it completely makes sense that if she wants to revive a forum for fans it would have to be a new one. I was never personally (or even peripherally) touched by the Tammy-related drama on Sheroes, but it always seemed like she was in an awkward place there; as an an author, she couldn't really engage in the fannish banter, speculation, and discussion about her books that often swerved into speculation or fandom, but she wanted to engage with her fans as a kind of on-line mentor. But her books were the area where she had authority (to a point), whereas, especially as the Sheroes demographic got older, her identity as The Tamora Piere, Author of the Tortall Books, was less and less relevant for that more general discussion.

Basically, I think it's really hard to make an author-organized fan forum work, and, also, Tamora Pierce is not as influential and significant a figure for her readership as she perhaps imagines she is.