I'm
extremely open to finding a better solution to React/Redux, but your example makes very little sense.
> in redux the reducer updates the model as: state.counter += 1 ;
That's not how Redux code would look, nor is that how Redux state works.
> you should write it as: [...]
That actually looks very much like how you'd actually write a reducer. Can you please clarify how you think this differs from idiomatic Redux code?
> Redux does not have any next-action-predicate
Inventing terms does not aid in advancing a discussion, especially if you do not define them. But reading through the OP, it appears that a next-action-predicate is just a selector, or possibly a selector used to implement what in Redux would be solved my middleware? The description is quite cryptic, but it at least claims to solve a problem which is already solved cleanly in Redux, which rather raises the question of what the advantage it yields is.
I mean this nicely, but: You're not really convincing me that SAM is a different pattern. Perhaps a simple example app? Ideally some small idiomatic redux todo app ported to SAM; that should show the differences (and benefits) very clearly.