One of the things that jumps out at me is her hands at the level of the ball at contact. I suspect her mental image of the swing is the barrel level to the ground at contact. What we want to see is a diagonal swing plane angled to the pitch location, resulting in the hands being above the ball at contact, and the barrel working in the plane of the shoulders.
As others have commented, we are seeing a swing largely driven by her arms, which is not ideal. If this was a hitter I was working with, I would introduce the idea of using the hands to turn the barrel to contact (forearm rotation) and connection to the torso with this kind of work...
You can be open and still stretched and coiled. Actually can/should enhance those things.I don't know if this was in reply to my post, but I will just ask, What is left for her body to do if she is already opened up like that. How can she perform any of the things such as turn the barrel or tilt etc.? She would have no choice but to power it with the arms around the ball, correct?
Core pulse!!She needs to learn how to use the obliques correctly and allow APT, and PPT to happen on its own. APT PPT is what's causing the leveling of the arms.
Using the obliques
You can be open and still stretched and coiled. Actually can/should enhance those things.
Added: check out Donaldson here: 4:45 minute mark.
She has made progress.He is talking about the front foot landing open, To allow the rear hip to work. I'm in full agreement with you that the hips can and should open, and the upper half stay stretched. But the way in which the OP's DD lands at toe touch cannot allow the rear hip to work properly. And to allow TTB etc. Again its just my 2 cents. Not saying right or wrong.