Actually kinda reminds me of a javelin throw.
Or a jai alai pitch.
Point is, don't get tripped up over the general body mechanics compared to the very specific requirements of a sport's movements. On many levels, athletes are athletes and they should train quite similarly, regardless of the sport or position.
The thing to remember with any kind of sports performance is that you get better at it by practicing it specifically. The gym is for building strength, power, and health, but you're only going to "perform the movement as well as possible" by performing the movement, having a coach watch you, and refining your technique.
With that covered... like Aragorn said, Cressey is definitely the go-to with baseball-throwing stuff because he works with a ton of pitchers. Elbow health, shoulder mobility, and transferring power from the feet through the torso into the pitching hand are all crucial. Other general stuff like power training for explosive strength, unilateral work to address imbalances, and basic pure strength work (for upper and lower body) will all play a role in being a better thrower.