There is some truth to the statement that generally tall pitchers are “better” than short pitchers.
But the statement is not one hundred percent accurate.
More potent a trait for a pitcher is the arm he is throwing with, in contrast to the side of the plate the batter is standing. A left hander almost always has more success against batters standing on the right side of the plate than the left.
And visa versa.
The body of the pitcher hides the motion of the arm and the ball, giving the batter less time to respond.
But the physical trait of height is also a factor. The taller the pitcher, the more downward motion is put on the ball. This assists the ball in moving in response to gravity. The angle of the downward motion creates a lift under the ball causing it to move up or side to side, based on the spin the pitcher puts on the ball.
The strike zone is also slightly larger for a taller pitcher. As the ball approaches the strike zone – generally a rectangular area of the measure front to back of the plate, and from the knees to the belt or the letters on the batters jersey.
While the strike zone is a perceptual target, the perception of the umpire is key. A ball traveling downward at the batter will breach the strike zone usually from the top and through the back of the rectangular zone. The taller the pitcher (within reason) the greater the reach from top corner to back corner.
The perception of the zone in the umpires eyes is altered as the pitcher grows taller.
This is why the pitcher throws from a mound. To provide that slight advantage.
There have been some tremendous tall pitchers. For example, Randy Jones is a very tall lanky pitcher with great speed, control, and variety of pitches. But Mr. Jones is predominantly a side armed pitcher. And Mr. Jones is a left handed pitcher.
There are so many variables to take into account to propel a baseball fast enough to be considered a good pitcher. Arm speed, strength, the ability to grasp the ball to move the wrist through the motion as the arm follows though, followed by the kinetic transfer of weight as the body follows through, and the timing to optimize the effect of all points combined.
For my money, I will take a left handed pitcher rather than a right handed pitcher almost every time. The advantage of height is “highly” overrated.