At his age you won't see a dramatic increase in 60 times.
He trained his body to be a line backer in college. He was carrying the weight of a football player.
Now the most important thing with him in the OF is reaction time and technique. Most players can get by with speed. But if you look at Almora he is near perfect with his instincts and technique. Those two abilities give him greater range.
Schwarber pretty much catches every thing in his range but there are 3 ways to increase range.
1. First step. Which is a combo of reaction time and explosiveness. Which from some of the training instagrams is the drills he has been doing.
2. Route path. This can be tought. Sori was tought I his and if he can learn...
3. Increasing top end excelleration. And to be honest this bit is pretty easy to achieve. Not saying he will be a speedster but better than he was.
Now as far as a lead off. Let’s face it Theo is from the OBA school. Sb = decrease in OBA. Even if you are steeling at a 60% clip that decreases OBA by 40%.
That link I showed the was #7 in being able to advance a extra base. Now I would like to see some of this metric for 2017. You would figure it would be lower with his knee recovery but still a interesting metric regardless.
Other than that it has to do with him getting over the shift. That will be his biggest challenge and losing weight really has nothing to do with it. Maybe make him a bunt threat if his times to first increase.