Replying to myself, since I can't edit my post anymore --

Futures and promises aren't unique to Clojure. For example, AliceML had them ages ago.

After thinking it over, I'm going try implementing them for my ExtCore library for F# (https://github.com/jack-pappas/ExtCore). Thanks to the GP for the idea.

CSP gives you everything async/await gives you, plus more. Channels can act as throw away promises, or as continual streams of events. Add to that the power of alt! (http://clojure.github.io/core.async/#clojure.core.async/alt!) and you got some very powerful primitives. There's nothing about async/await that's really new. You can implement these on top of yield (C#/Python), or with any language that supports the pausing and resuming of execution.

In Clojure CSP is implemented as a library (core.async), no changes to the compiler needed. Now that's power.

(disclosure, I helped write core.async)

async/await is just a generator function that yields promises. It is implementable even in node.js if you enable --generators flag.