Pulling in a sort-of success story from another large project, I like the general way things happen in Django.
For developers proposing an idea or fixing a bug:
* There's IRC (#django-dev) for quick, synchronous-ish discussion, useful for someone to find a sounding board for an idea
* There's a dev mailing list where proposals can be discussed a bit more formally
* There's the public ticket tracker as a place to follow work being done
And for users seeking help or general discussion:
* There's IRC (#django) and a users mailing list
* There's an official-ish subreddit moderated by committers
* And there's the rest of the internet, including Stack Overflow, which we can't moderate but which many experienced people in the community do pay attention to
We've avoided using GitHub issues for Django, preferring the workflow tools we get from our own customized Trac instance.
I wonder whether something similar -- a real-time chat for discussion/sounding board/etc., mailing list to bring things to once they've been thought about a bit, public tracker for following work/archival purposes -- would work for packaging.
(I am also wary of too much "process"; Django has a fair bit, and more than I'd ideally like, but my experience has been that process and participation are generally inversely correlated)