The Return of the Historical?

Melissa pointed out this post from agent Kristin Nelson's blog Pub Rants. She says editors are asking for good historical romances. For years, the genre has been on the decline, but apparently it is on the upswing. When I signed with my agent, I told her I also wrote historicals and she said great since historicals are coming back. So Ms. Nelson isn't on her own in this. I do wonder, however, what kind of historicals are being looked at. Is the spectrum broadening for eras and settings? What do you think? I've seen the emergence of historical paranormal romance, so it seems as though their is a sense of adventure needed. More danger, more darkness? Is this style of romance going to outpace the light historicals?