That's super cool.
The things that spoke to me, first was that she not only talked about the dichotomy of the "relaxed arm/ arm weight" school vs. the "fingers" school and her own experiences with that - she also goes beyond. The arms are an integral part of arms, hands, fingers and the torso, and they are active parts: not just relaxed limbs that plop down through gravity. She shows a video of her old playing that could look ideal, but it was just before injury.
There is another part that I found extremely important and I barely ever see it mentioned. That is the 3-dimensionality of our playing field. The keyboard itself is a flat surface like a floor, with spaced black key "bumps", but the space our hands traverse is 3-D, up and down, in and out. Equally important is moving from one key to the next, including your hand doing that moving, as opposed to your fingers being "posed over" all the keys you'll be playing. If I will be playing C, E, G, C', G, E, C , I don't need to have each finger hover over those keys, or even just over the E, and G while playing the C.
These are things I'm working with right now, before seeing the video. My hand still tends to live in a rather shallow almost 2-D world. I'm using a slow, measure-by-measure Chopin Op. 25-1 to retrain, because the distance between the keys is large and varied, so that you have to move from key to key, and effectively.
She also mentions that Chopin referred to "high keys" and "low keys" rather than black and white. There are things that people who move normally might "just do", that I don't. For music that has notes closer together, which resembles the music I played as a self-taught child (sonatinas mostly), I had the most difficulty. Going from a black to white key, such as F#, G, I struggled for the white key to sound as clear when playing faster. Well, golly gee - if it's lower down, you can lower your hand a titch! (She shows that about midway through).
I've often found that I was missing things that were "too obvious to explain", and those "obvious" things were exactly the secret ingredient I needed.
