See Are Twins Taking "Pitching To Contact" Too Far? by Rob Neyer.
To look at this, I calculated the batting average and slugging percentage in the AL in 2010 on contact. For contact, I used AB - K + SF. I assumed that sacrifice hits (bunts) and their attempts rarely end up in strikeouts. So in the AL last year when a plate appearance ended in contact, the AVG was .320 and the SLG was .501.
How many runs per game might this lead to? To approximate this, I used the equation
R/G = 16.04*OBP + 11.595*SLG - 5.52
That comes from regression analysis based on the 2007-2009 seasons.
Last year the AL had a leage OBP of .327 and a league SLG of .407. The equation predicts that would lead to a runs per game of 4.44 (it was actually 4.45). But if we used .320 for OBP and used the .501 for SLG, we get 5.44 runs per game. That seems like a big difference.
I am not sure if this approximation works. It would be quite a different game with no walks and the denominator for OBP and SLG is not the same in each case. But even with that said, I am skeptical that pitching to contact (or not trying to cause batters to miss the pitch) is a good idea.