The business end of a short lever more closely follows the path of the hands and has a shorter path to the ball.
Somewhere I once saw a hitting video with Tony Gwynn, made long after his playing days, when he was coaching college ball.
He was swinging some sort of wooden hitting-aid bat, one that had a much larger knob on the end and even bigger knob between the hands and the barrel. I imagined that it was designed to change the weight distribution of the bat. A bat has almost all of its weight in the barrel, but by choking up on a biat you've "counter-balance" that weight distribution. I think that batting-aid was trying to do something like that, in an exaggerated manner.
I apologize for going back to golf, but I think it can apply here: When you choke up on a golf club, you've "counter-balanced" it. Not only are you swinging a shorter lever but you have changed the feel of it, too. That changed feel makes it really hard to "swing for the fences."
For a long time I made my own golf clubs. You know, buy the shafts, heads, ferrules, and grips. Cut and epoxy kind of stuff. Probably used 6 different drivers that I built and 4 different sets of irons. I go back and forth now between two home-built drivers (one shorter than the other), but being a dinosaur I've put back in my bag a set of Titleist blades I bought in '86. When building drivers, you quickly learn that adding length (made doable by lighter composite shafts) adds "swing weight," which is an expression of the weight distribution of a golf club. Two golf clubs of the same total weight, but of differing lengths, do not feel as if they are of the same weight. The longer one feels heavier. One of my two drivers is one inch longer than the other, but because the weight is a bit further from my hands, it feels as if I have to really get after it. The difference between 45 and 44 inches "feels" significant.
Shortening a driver by 1 inch changes its swing weight by 5 or 6 pts, which is a huge difference in terms of that "feel."
Some players have experimented with counter-weighting the club (using a grip with a weighted butt) to change the feel and reduce the swingweight.
The same must be true of a baseball bat. It is why choking up on a bat makes it feel so different.
Per Doc, above: A shorter 40 oz. bat will have a similar "swing-weight" to a longer 34 oz. bat.
Get Zunino to choke up 2 inches and you've changed the feel, making it more "unnatural" to swing for the fence. You've also created a shorter lever with a shorter path to the ball. A shorter lever is always easier to make solid contact with. It's why hammers aren't 2 ft long.
I'm not trying to be a yahoo here. A simple fix for Zunino is a quick fix. I want him back and I don't want him thinking about mechanics.