Don't throw a Destroyer at Calvert, wait keep doing that, I don't want you to throw far, you beat me every round except the last on the green monster. The issues I see are pretty much what you noted, footwork, and clearing the backswing and downswing. You are not using your hips/transferring weight properly and getting too open, limiting snap potential and core power. Teach me to putt/approach and I'll teach you to throw far.
Pay special attention to around the 2 minute part where he talks about spinning out.