Bill Clinton took a big political hit from Hillary's health care attempts, and she is highly polarizing. Yes, she may still be able to excite some feminists and Clinton Camelot voters, but it would be very hard for her to win at the top of the ticket this year, let alone as a last minute replacement on a ticket that features a guy that many independents have had it with.
I never underestimate the ability of the voting public to gloss over the details and vote as though they were watching American Idol, but I also believe that people vote their best interest, and a large and growing number of people don't believe that Obama is in their best interest.
What would Hillary's message be? We're going to change things from the way they've been done the last 4 years? How's that gonna sit with Obama, and how does that sway people to vote for a ticket that features him at the top? If she says ‘we still have work to do. Let us complete it’, that just tells everyone that she's onboard with a continuation of the Obama approach. Not a very comforting thought for a growing number of people.
In fact, my suggested approach for the Romney campaign if this were to ever happen would be to play exactly that angle. ‘Are we now going to do it Hillary's way? Then why are the democrats running Obama at the top of the ticket? Where was her advice over the past 4 years when the economy was floundering, the debt was increasing, and people were suffering? If she had good advice, and the President didn't listen to her, why will he listen now?’
Just my humble opinion.
Now, with Hillary joining Obama's ticket, will most voters think it through as you have, or will they think "Hey, remember how great things were when Clinton was President? Let's go back to that!" That's why I keep saying we need to have answers for "Clinton's economy" ready.