One of the more frustrating aspects of the Royals' season this year was the lack of offense under Tony Pena. Too many times it seemed Pena was playing for one run, and many times that's exactly what they scored.
In Pena's 33 games this season, the Royals averaged 3.545 runs per game. In interim manager Bob Schaefer's 11 games (small sample, I know) they have averaged 6.09 runs per game. Pena's deficiencies are clear when comparing his managing style to Schaefer's. On the day he took over, Schaefer declared that his team would play more aggresively, and it has paid off.
This style goes against most "Moneyball" principals, where plate discipline is stressed. The Royals have been swinging away, not waiting for a walk but putting the ball in play. Whether this is how they should play in the long term is debateable, but when you are desperate for wins and the offense has been as bad as it was under Pena, it makes sense to be more aggressive to get things jump started.