I think her stance is fine and in many ways I think the front leg is a no-teach other than to be certain it isn't collapsing and that she's hitting into a firm front side. I think if she's more explosive with her lower half (back leg) driving to the ball that such an action alone would get her into her legs more as she swings and will help her get on plane longer. I'm not a proponent of doing it artificially with the stance itself. You don't need to listen to the audio as I don't know if it's any good but look at back leg on Trout video at about 2:30. https://www.youtube.com/watch?v=-BZgZuI6hSw