Here are a couple thoughts to consider:

1) Try positioning the ball more towards the inside on your approach. Looking directly behind you in the video I can see the ball starts very far toward the outside, which will naturally cause you to bring your backswing behind your back. Starting the ball closer toward the center of your shoulder or even a little further to the inside will create a more natural backswing movement to the outside part of your body.
2) Strengthen your wrist! Start by getting a light dumbbell (e.g. 5lbs) and do wrist curls. Do sets with the palm facing up and the palm facing down. Do you wear a wrist brace because of a previous injury or because its weak? If you are wearing it because its weak then ditch the brace. You'll never be able to create the wrist strength and wrist movements needed to load and unload the ball.

I'd rather give you only a couple things to focus on rather than a laundry list of items to think about in your next practice session. Hopefully this helps.