I don't think your backswing is too high. The major problem is that you are ultra late with your timing. Your slide is almost complete before your ball starts to drop. This is causing your slide foot and hips to rotate at the line and is also causing the huge leg kick.
If you want to focus on something to correct these errors, work on getting the ball into the swing earlier. The ball need to start moving as you take your second of five steps. You currently start your pushaway about halfway through your second step.
If you are still having trouble keeping your trail leg down and slide foot straight, I would suggest doing Joe Slowinski's one-step drill. Start close to the foul line with the ball hanging at your side and your right foot just a bit ahead of your left. Swing the ball forward and up about to the height of your current pushaway, allow the ball to swing to the top of your backswing. Once you get to the top, simultaneously start your slide foot forward and allow the ball to start your downswing and release the ball at the bottom. Focus on remaining balanced and try to keep the trail leg in contact with the approach. What you are doing is training your body to learn earlier timing. Do this several times and then mix in a few full approaches. Try to get that feel of the ball and your your slide step moving to the line together.
Take at look at Chris Barnes in this video.
http://media.putfile.com/Barnes-and-Me-comparison Watch how the ball drops right as that slide leg is moving forward. That's what you're looking for.
You got a lot of good things going on in you game. You just need to clean up some timing issues,
