"But it is in fact time for those who think Hillary has a better chance against McCain to say exactly why."

McCain is far too old to take the job and the voters know this.
It will be Romney.

Hillary is an extremely powerful speaker who happens to be very good in the corners.
Obama is the weak link. That is why the media is pulling for him, for the time being.
I'm with Sorcha.
I would not be surprised if the decision has already been made.
Having said this; Hillary has done a fine job of overcoming a biased news media and fudged election polls.
Her results in Florida are an example of how well she can do with an uncontaminated electorate.
It will be Clinton/Edwards versus Romney/? with the Republicans winning by a respectable margin.