Katie Couric debuted her daytime talk show yesterday to mixed reviews but the best preliminary daytime premiere ratings in a decade, since the first outing of "Dr. Phil" in 2002. "'Katie' debuted on Monday with a 2.8 household rating in the 56 U.S. metered markets, trumping the recent debuts of 'Steve Harvey,' 'Jeff Probst' and 'Ricki Lake,'" writes Brian Steinberg.