The drill one 430 path drill stops the right arm from straightening- allows the body to open and turn- and keeps the golfer pushing force into the ground through the feet and legs. It also sets up the drill three post impact that keeps pressuring the shaft to the finish.
Most golfers- even PGA Tour players- have habits they gravitate towards that can cause their swing to not perform as well. Nobody is immune to this.
Connection- Power- Force...How do they all tie in? 
The end of the club is hidden by the hands but here is a visual drill that can help the golfer see and feel where the shaft should align to create consistent strikes on the ball. 
How do consistent ballstrikers get the clubhead to enter the ground at the precise point that allows pure contact. Watch and learn.
I get many comments about a video I made several years ago named "Out Is Down". Here is another example of it -with Patrick Reed- showing how hand path and club path are different.