I think there is no question that Bill will play a big role in a Hillary Clinton administration. Even back in 1992, they were telling people that they were going to be a package deal. Given his political skills, his connections, his knowledge, and his experience, I think he's going to be far more influential than anybody else in the administration (especially whoever the VP is). Bill might even end up being the main decision maker. He not only knows about all of Hillary's skeletons, but he might even dominate her emotionally and psychologically. That's probable in fact, given his personal charm and prodigious intellect. His philandering past may even make it more likely (I'm not a psychologist, but I did stay at a Holiday Inn Express a few weeks ago).
As for whether or not Bill's record of sexual harassment should be an issue, I'm agnostic on the question. He's probably too old and sickly to do anything so outrageous as to cause political problems, let alone national security problems. On the other hand, it sends a bad signal to sweep his past under the rug. If Bill Cosby can be prosecuted for sexual abuse that happened decades ago, surely we can feel queasy about putting a credibly accused rapist in the White House (and, yes, Juanita Broaddrick's accusation of rape is highly credible in my opinion).