It's the only thing that they are just dead last in. Ok, they actually passed the Giants last night, now at 31.7% of pitches outside the zone swung at. The Giants are at 32%. Patience doesn't guarantee you'll score more runs, but the top 3 teams in least balls chased:
The best teams in this category
Yankees 24.1% (1st in division)
Indians 24.9% (also 1st)
Rockies 25.3% (1st)
It seems to me that taking more pitches will have the following effects:
more stress to opposing pitchers
more often facing a pitcher from stretch instead of the windup
more people on the bases
more strikouts as less balls are put in play early. If they take more pitches in general they will probably also take more called strikes, but hopefully at a lower rate.
Think about it from the pitching point of view. It's bad when your pitcher is racking up a lot of deep counts, and especially bad when you walk people. Ipso Facto, as a hitter, it must be good when you cause that to happen. The Cubs need an alteration on their hitting approach.