Seeing the video she is the definition of all arm. To [MENTION=332]sluggers[/MENTION] point in addition to the lack of resistance in the leg, her torso is doing the same thing with the bend. Beyond that there is the rear shoulder and hip. Job #1 is to fix the front side, then move on to the torso and get things firmed up. Then you can work on other things like the long arm circle, etc. To the point of the OP, the foot is way down the list. The good news is that with the right focus and hard work she will be a much better pitcher with improvement coming a pretty rapid pace. All that said, do not try to fix it all at once. This will take some time, keep the focus narrow and do not rush the process.