Just because you played high school, college, or professional baseball, that does not mean you understand proper hitting mechanics. Even Hall of Famers do not understand how they actually moved their body and their bats. They confuse feel with what is real. They may feel like they are moving their body and swinging the bat a certain way, but slow motion video shows us that the real movements and swing are different.
Having played baseball at a high level is certainly useful, but it in no way means you can teach hitting particularly if you do not study the high level swing.
Alex Rodriguez batted .295 with 696 home runs. You would think he understands how to swing a bat correctly. However, in this video, Rodriguez advises batters to swing straight down to the ball (1:36) and demonstrates a chop (2:21). He also makes the bogus claim that you swing down to get the ball up in the air and produce backspin (2:05). High level hitters do not swing down (chop at the ball). Moreover, swinging down is not the best way to produce backspin. Rodriguez also claims that batters use a “Ferris wheel” swing to get a greater launch angle, which results in a “long slow swing” (1:45). The problem is high level hitters who increase attack angle to increase launch angle do not dip the bat and get disconnected as Rodriguez assumes (2:20). They stay connected by increasing shoulder tilt to produce a steeper attack angle. That does not create a long slow swing because the bat is not casting away from the body as as he suggests.
George Brett is in the MLB Hall of Fame with 3154 hits and a .305 batting average. Nonetheless, he does not seem to understand the position of the batter and bat at the point of contact. In Charley Lau’s The Art of Hitting .300, Brett demonstrates the ideal position at point of contact with the arms fully extended in a Power V and shoulders square or perpendicular to the bat.