Yes, he just would have to explain peolpe why conservative policies since 1980 caused a catastrophical and useless crusade and an economical crisis due to a blind "laisser-faire" ideology. In synthesis, why conservatism ruined America. You're right, nothing more simple !
On that particular count, actually, John McCain had the same problems as a far right Republican would have had. (And Obama hardly represented change, anyhow. 
)
Only because he chose to compromise himself with the conservative religious right : his pick of Sarah Palin meant exactly that. And it was a dramatic erroc : had McCain not done this, he could have come much more close to Obama. But GOP os today the prisoner of a disastrous strategy, to mobilise an hypothetical "conservative grass roots". It worked once, in 2004, but definiteli disgusted indipendent voters.
Actually that is not true at all. Sarah Palin closed McCain closer to Obama then he was before the pick. The economic collapse in September finished McCain.
I think there's a lot of ambiguity over Palin's later effect in light of the economic collapse that followed during it, but considering her introduction was a lot better than her follow-up, I don't think you can make a concrete conclusion either way. I tend to think that it hurt the "brand" long-term, but I can't really prove it either way.
Her approval ratings did decline, IIRC, to the point where they were a drag on McCain and the ticket but maybe I mis-remember.
