You can build analogous versions of map/filter/etc on top of channels. The core.async team is still focused on the primitives, but surely some higher order operations will follow in the not too distant future. I suspect we'll need to wait and see what patterns develop, since they will surely differ from Go a little bit, due to the functional emphasis on Clojure.

I should also mention a key difference between channels and Rx/Observables: The fundamental operations for observable sequences are subscribe & unsubscribe. The fundamental operations for channels are put and take. In the push sequence model, the consumer must give a pointer to itself to the publisher, which couples the two processes and introduces resource management burdon (ie IDisposable).

You can think of a pipeline from A to B in the following ways:

Sequences: B pulls from A

Observables: A pushes to B

Channels: Some process pulls from A and pushes to B

That extra process enables some critical decoupling!