There is no way in the world McCain would ever beat Obama in the general. An Old DC centrist-liberal lacking strong conservative base support against the first Black Candidate with strong liberal base support running on a Change platform. The Iraq Police Action would be a non-issue by then, which is a good thing. There is no way McCain could beat Hillary in the general. Dole could not beat Bill even after the 1994 revolution. Now we have a Dole retread running up against the First Woman President in our History. Hillary would not have strong liberal base support and McCain would not have strong conservative base support. Hillary has large negatives, but so does McCain. The race would break on the 'First Woman President' issue. So to nominate McCain is to elect either Obama or Hillary. The Republican nominee has to have strong conservative base support if winning is the goal. IMHO.
You are quite off. Hillary has the worst negatives of any candidate running. But on the other hand, John McCain has the highest net favorability rating (consult Rasmussen).
The 1996 comparison is bunk for three reasons: Dole was running against an incumbent during a booming peacetime economy, McCain is a very energetic campaigner sometimes holding six or seven town halls a day tirelessly taking questions with a press meeting after every event (his staff literally needs to pull him on the bus to get to the next event he is so engaging), and Ross Perot siphoned off a lot of votes that would’ve went GOP that year.
Here’s the key to Hillary and there’s no way around it. I’ve cited her negatives and McCain’s favorables. But put simply independents loathe her and like (even love) McCain. Every occupant of the Oval Office is the one who wins independents.
As for Obama, I don’t expect he will win the nomination but if he were he would also be quite open to the charge that he does not have anything close to the experience needed to be POTUS. Never in recent times (going back many decades) has there been a nominee as inexperienced as Obama. McCain on the other hand is very much experienced would provide a stark contrast. We are at War lest we forget - the voters won’t forget either.
Finally, some polling to chew on...
Ohio (Survey USA 1/7):
McCain 50
Obama 43
Romney 39
Obama 51