Re: "Slight Uppercuts" vs "Level Swings" and "Chopping Wood"
Hitter A is an average hitter with good potential. Hitter B is a good hitter with great potential. Both hitter A and B make adjustments to their hitting mechanics that maximize their hitting potential. Hitter A is now a good hitter, and Hitter B is a great hitter.
Each "hitter" has a certain maximum "level" that they can reach. Joey Votto is one of the best pure hitters in baseball. He was born with that innate ability, however, it was through thousands of swings, changes to his hitting mechanics, and years of hard work that he became the hitter he is today.
The idea that you cannot improve your swing through adjustments to your hand position, foot position, etc. is crazy.