IMO, it's the "how" that's the challenge if you want to be a successfull hitting instructor. Often times high-level athletes are among the worst at trying to teach how to do something because they don't actually do what they think they do. It's about being able to communicate with individuals with varying levels of ability and different learning styles.
Obviously, you can't teach hitting without knowing "how" it is done. But how hitters hit is visible in slow motion video. That is the point.
When looking at high level swings you can look at them in slow motion, or even frame by frame, and see exactly how they swing the bat. The key is understanding "why" they do it that way. "Why" does the hitter hold the bat the way s/he does? "Why" does the hitter move the way s/he does? If you understand the "why", the "how" begins to make a lot more since.
How and Why are both critical to understanding the high level swing. It makes it much easier to determine what aspects of the swing are important mechanics, and which are "style". How Pujols holds the bat is not debateable because we can see it on video. Why he holds it that way IS debateable and the answer can lead to a better understanding of propper grip and hitting in general.
The better we understand, the easier it is to teach, because it can be taught to different hitters by useing different methods, depending on their ability to learn.