Or more specifically, the pre-dates. Answer: It's pure speculation. Actually, it's tactics wrapped in speculation. Or speculation about tactics. Either way, it's fun and easy for the press to play.
It's the same reason the press wallowed in the pre-VP announcement announcements, spending days and even weeks playing the what-if game. It's the reason the press gorged on the convention coverage, specially in Denver as pundits speculated non-stop about how the primetime speeches, especially by the Clintons would play out.
The press in this campaign has really elevated speculation into an art form. Because why? Because it requires no actual reporting. It often doesn't even requiring calling people up for quotes anymore.
Take this pre-debate piece today from the Chicago Tribune. It's nothing but speculation about tactics. This is what now passes for analysis.
Tribune tip for Biden: "please don't smile." Tribune tip for Palin: "Be likable, but not perky."
It's theater criticism run amok. And that's why the press loves debate season.