Shoulder disappearing then reemerging... blending with uke's push when needed... not if if not needed. Each uke is so different.
Granted. I agree.
As an added bit of interest your description reminded me of something I was taught or rather shown many moons ago and although it's not really to do with hip/shoulder it is to do with turning and then turning back.
I was wondering how comes the teacher could turn me back and flip me with hardly any movement from himself. He showed me what it looked like if done so that I could see it. He proceeded to take my attack and lead me around with a complete tai sabaki and then turn back with kote gaeshi. All very slowly and comfortably.
He said after lots of practice and focus on the flows and energy of such basics you can already have it done which looks to the outsider like a short cut or something totally different. Yet energy wise it's the same as that slow well recognizable form.