Promises are going to solve this problem in an elegant way, expect it in next major release.
That said, I've release a client/server game (online sailing regattas) in Elm & Play/Scala with websockets, and current API was enough for me:
https://github.com/etaque/tacks
Anyway, that's why I'm supporting my job : that mental and physical reboot through sailing every week-end became essential to me. Finding your own weekly brainwasher is a fair compromise !
One friend of mine did the same, here in France: high level degree, but only one year working in front of a desk. He totally switched to a sailing instructor job. As a computer engineer and sailor, that's really appealing me, but my skin wouldn't bear it. I know he's 100% living during the day, I know I'm making mouldy on my chair...