This looks very interesting but I have one concern: Wouldn't code where the "view" part and application logic are tightly coupled be way harder to test than an

This looks very interesting but I have one concern: Wouldn't code where the "view" part and application logic are tightly coupled be way harder to test than an architecture that renders the view in a pure function and does state management somewhere outside entirely? (Which is not what React is today but might correspond to the original idea.)