Your weight is still too centered throughout your throw, It isn't far enough back at reachback, or far enough forward at the end of your throw. As JR said, getting your weight forward has nothing to do with leaning. You want to be balanced above your left foot at reachback, and right foot through the pivot.
If you insist on using a runup when you practice, try to take a longer crossover step (push off harder with your right leg and reach further behind you with your left, you may have to get a little lower to the ground to pull it off), and a shorter plant step. This will put you more over that rear foot when it lands, netting some more forward momentum into the plant, and make it easier to get your weight forward when it needs to be. You're already developing a pivot hop step when you runup, which is good go with it. If you haven't seen Feldbergs video on that, you might want to check it out.
One of the things that really jumps out at me is the way your left foot is already dragging behind you , when it needs to still be firmly on the ground, pushing your hips forward to aid/initiate a strong follow through. I could be wrong but I think that means you burned up all your hip power earlier in the throw, and your upper boddy is pulling your lower body around, when it needs to be the other way around.
There's a couple key concepts missing from your throw, and they're just not something that you'll stumble across randomly practicing in the field unless you've got a sports background or a lot of natural ability, of which I have neither. I had to practice for ages to incorporate them into my throw, which looked similar to yours a couple years ago.
I already basically posted this same thing in another thread but I'll see if I do a better job of explaining it this time. Check this thread out for original content: http://www.discgolfreview.com/forums/viewtopic.php?f=2&t=16139&start=165
The short version is goes something like this.
Simply planting from full reachback(1), and NOT trying to twist or turn or do anything but shift your weight, will turn your hips and shoulders 90 degrees, generating enough momentum for you to sling your arm all the way out to the right side(2-4). Notice how the hips are not
leading, and the shoulders do not rotate as the disc goes across the chest. Keep in mind that in frame 4 (this is where your foot is trailing behind)you need to be in position with your lower body PUSH the hips around/forward with the rear leg (think of them being on a hinge with your right leg/hip). 4-5 is where you should feel the big coil/uncoil, which is greatly aided by your weight going forward. This is what lets you accelerate into/through the direction change of the arm, which is what really throws the disc, which gets a great illustration on page 3 of this thread http://www.discgolfreview.com/forums/viewtopic.php?f=2&t=24903
You're making progress, keep at it. I hope this helps.