The theme is that pretty much all those guys hit at the top of the order, giving them more plate appearances in front of good hitters. Think about what you're saying for a minute. Dunn gets on base more often, and hits for extra bases more often than all of those guys(i.e. he puts himself on the bases and in scoring position more often). Do you really think the difference in runs is because those other hitters hit singles(or in the case of those with a lower OBP, hit into outs) when Dunn walks?