I believe that the LA Times sat on the story because they concluded that if they took down Arnold earlier McClintock might win (heaven forbid), and that Arnold is the lesser of two evils from their perspective.
Think about it. By releasing the info 5 days before the election they look transparently biased, and must know that what they reveal will be viewed through that prism. They can say they've done their journalistic duty while having a relatively minimal impact on the final result.
Jill Stewart claimed on Fox today that the story has been ready for two weeks. Two weeks is before the one debate Arnold was in. A story just before the debate COULD have brought the walls tumbling down on Arnold, or at least blown the race wide open. And who knows how big the avalanche of "gropees" could have been? The guy who wrote the Premier Magazine article claimed on Drudge's radio show last night that the potential list is way longer than 15. By that time Busty had shown himself to be a total loser, so any movement would clearly have been towards McClintock. In that situation, the LAT decided to hold their fire to save Arnold.
I suspect Mr. Carroll and Co. at the LAT are toasting their cleverness at the moment, confident (perhaps falsely) that they can overcome this body blow to their credibility. They've pulled a Dunkirk maneuver, and they'll be back to fight another day.