I have always been a fan of batted-ball stats. The most fundamental goal of a plate appearance is a hard hit ball. Guys like Billy Butler and Eric Hosmer learned that to be really, really good, you have to hit the ball hard in the air. But you can work with a high exit velocity. There’s a reason why Hosmer and Nicky Lopez have very similar groundball/flyball profiles but one has a career 107 wRC+ and the other a career 73 wRC+.
Batted-ball stats are helpful because not all outs are created equal. An unsustainable BABIP turned Lopez into a 6 fWAR player for a brief moment.