Documentation can't help with "judgement on the entire space of all possible future feature additions to a complex system."
Suppose foldable Android phones are a thing now (they are!). You want to make it easier for developers to build great Android apps for foldable phones. Can 3 engineers really do all this in a few months?
* Android SDK changes?
* Jetpack compose changes?
* Android Studio changes?
* Material Design changes?
* Flutter/React changes?
You can't pre-document this.