It sounds like it wasn't decided to keep 3rd party as much as decided not to not combine yet:
> The feedback I got during the proposal process for putting Channels into Django 1.10 (it did not get in before the deadline, but will still be developed as an external app with 1.10) was valuable; some of the more recent changes and work, such as backpressure and the local-and-remote Redis backend, are based on feedback from that process, and I imagine more tweaks will emerge as more things get deployed on Channels.
It seems to be taking more of a South approach, and I really like this. Shake out conceptual issues, find an API that works well, iterate a bunch. Django release cadence is pretty slow, so having it simmer outside of it makes a ton of sense.
If it's a big hit like South was, it'll get rolled in and we won't have to immediately start deprecating things due to an un-tried design.