Our architecture has quickly evolved in that direction however: Higher-order React components mediating almost-declarative store accesses with all the back-end fetching, optimistic updating, etc handled transparently by common store logic. All objects within a store are flattened down into an id -> object immutable map with conventions for indicating a given object is loading, loaded, in-error, etc.
We'll be having another serious look at it soon. It will be interesting to see if we'll have an impedance mismatch between how we've built our data model on the backend such that GraphQL isn't a good abstraction. The idea of being able to declaratively express what you want to have in a given React component without having to write any store logic, etc, is super compelling.