Pomeroy does give extra weight to more recent games, though I don't know how much. However much it is, the efficiency figures remain volatile even after 30 games, as evidenced by the movement in the Final Four teams' numbers over the course of the NCAAT.
As far as solving our defensive woes, I think Coach K's presser was a good sign. He wouldn't have taken that particularly trick out of his bag it if he didn't think a public shaming might solve the problem.