Before trackman & foresight, there was John Jacobs who said the sole purpose of a golf swing was to produce a correct & repetitive ball flight… he went on to say the method employed was of no consequence as long as it was correct & repetitive. When I started teaching I was fortunate to be mentored by the older much wiser Jim Hardy who taught me and hundreds of teachers (via the Plane Truth). He taught, like Jacobs that swings were either pretty neutral and worked just fine or they were too shallow, too steep, or missed the radius.
As teachers we simply needed to be able to recognize which of three categories the miss hit fit into and solve for it. If a swing was too steep and the ball flight was a slice or a pull for example, I could instantly recognize the fault and take away steep elements Or add shallow elements until we were close enough to neutral to get the desired impact & ball flight. I think all teachers should be able to recognize impact & ball flight without radar and computers. It’ll make you a better teacher.
Want a fun challenge…close your eyes and listen to someone hitting balls and identify whether it as a steep or shallow impact.