I think that Kay Scarpetta and Lucy are *both* part of Patricia Cornwell's fantasy vision of herself, for the most part. I think that's why so many people are saying that they picture Kay as a tall, thin, blonde. I should note that I picture her the same way, and in my mind Lucy looks like her, except that for some reason I always picture Lucy as much shorter than Kay.
I always tend to think of Kay as a rather brittle WASP (see Cornwell, Patricia), but that isn't the story at all; she's supposed to be from a down-at-heel family from Miami. (Should we picture her as Janet Reno, then? LOL) Anyway, Marino comes off as stereotypically Italian, but the women most definitely do not.
I just read one of the newer novels after not reading any of them for years. As I read, my recurring thought was -- how on earth did Lucy turn into Batman?
As to Benton, yeah, it's strange, but he was always my favorite character in these books, so I'm kind of glad to see him. He seemed so normal in comparison to the rest of them.