Nice article. I have no answers, but I have one experience to share. I learned the feeling of "pulling the shoulder blades back and down" a while back when analysing my difficulty in getting my arms above my head in a tight streamline. It seemed that the more I tried, the more my arms would angle forward. Then I learned to work with my shoulder blades. Instead of reaching and squeezing higher, I focused on pulling the shoulder blades down. It helps and feels totally different.
Terry kind of got me started with shoulder blade awareness. I saw Terry demonstrate shoulder movements for Betterfly training, and he also advocates the "Scapular Push-up" shown in the article. Like many things though, I become aware, practise a little, then a bunch of time goes by before I realise that I had stopped practising!