How do you know she is a moderate? I see no evidence. You might be surprised once she starts weighing in.
She switched parties from being a Democrat to being a Republican, which to me smells like a moderate. And Harry Reid certainly seems to like her. I know some will say well she was a "conservative" Democrat. No such animal in my opinion. You are either a liberal or moderate Democrat.
Too late then if she turns out like Souter. The appointment is for life. That could mean 30 YEARS of bad rulings.