I find that over swinging almost always leads to more arm action just because it feels strong.
IMO over swinging is the result of a desire to want to hit the ball harder/further, but the reason for the "want" is misconstrued. The hitter thinks he/she is hitting weak balls because of a lack of swing power however the real reason for weak hits is generally mis-hitting the ball and the fix for mis-hitting the balls is very different than the fix for a lack of power.
IMO over swinging is the result of a desire to want to hit the ball harder/further, but the reason for the "want" is misconstrued. The hitter thinks he/she is hitting weak balls because of a lack of swing power however the real reason for weak hits is generally mis-hitting the ball and the fix for mis-hitting the balls is very different than the fix for a lack of power.