Agreed. I initially thought "this is going to make everything look so messy" but after I watched this particular video, it's clear that they've put so much thought into every scenario imaginable, including giving developers a lot of advice on when to use it, and when not to use it.

All that is very old-school Apple actually. Way way way more thought put beneath the surface than just meets the eye, when it comes to UI interactions.

I remember the inertial scrolling, rubber banding stuff on iOS. During those early days, people analyzed things like the navigation push and pop animations, and there was a lot more going on there than just "go left, go right"