It made me think me of Hunter Thompson's book about the 1972 race. He found people willing to vote either for Wallace or McGovern. Even though their politics were completely different, they were viewed as straight shooters rather than BS artists and so could be embraced by those who think all politicians otherwise are a bunch of crooks.
It seems to me that McCain has lost that luster. You can go back and forth about whether conservatives will embrace him (probably not, although Republicans are certainly more disciplined about holding their noses and going with a winner than the other party) or whether he'll still appeal to independents.
I think by trimming his sails he already comes across as a conniving politician and therefore nothing special to those who feel disenfranchised.