Coaches are a major contributor to the development of their players and the ones with the foresight, knowledge and integrity to challenge what is being taught in regard to hitting is an absolute gift to your players.
Oftentimes, players are trying to generate power with their upper body and in doing so they extend their arms and the process of the turn and separate from their lower body. If they have been trained to lead with their hands they will definitely separate, so re-training is a big part of the process for most players.
Don’t get hung up on torque, it has already happened. It is a split second and unless you are videotaping the swing you won’t see it. If a player loads 1-2 inches, a slight inward turn with their upper body and pulls with their hips at heel drop there is torque. And conversely, if there is no upper body very little torque will be generated if any at all.
Another culprit to be on the lookout for is the lack of weight transfer that initiates the entire swing process. Players that are squishing the bug lose a huge amount of energy and will have a harder time getting their arms around their body. When this happens separation occurs between the big muscles and the small. Once a player gets separated their power takes a nose and they swing path will be altered by the top hand, neither which are favorable to the hitter.
The barred out front arm is another problematic are and one which creates “bat lag.” When a player is lagging their bat, it is impossible for them to get into an ideal contact position. This needs to be hammered into your players, they have to “learn to turn” to ideal contact.
If you have a player struggling with the front arm, first check their weight transfer and then work the heck out of the contact drill. Keep it simple, keep it short and compact to the ball. Remember, the swing is broken down into two parts; short to the ball, and then long through it. Go back to the beginning and burn in the proper muscle memory. Learn to turn! I enclosed a video clip that demonstrates clearly what separation looks like. Keep up the great work, it will pay huge dividends.