That’s a very good question.
Public channels will need to be created as public topics under a category called Slack import
Private channels as private topics under same category or maybe another slack private category.
The “members” of each channel would need to either be mapped or created somehow. That’s probably best done by email address for example.
There is meta data for each channel that can be reused.
pinned conversations should be prioritized somehow not sure how
The issue is really the noisy thread/threadless chaos that happens in slack channels. Maybe just simply convert each post into a message and then threads become threads. Let admin clean up afterward?
Just a few ideas and concept.
The issue I have with slack is that the discourse degrades very quickly. I think a lot of that has to do with the fact it is all private. If people know that some content could be converted to a public forum they would behave.
Or at least what is interesting is that threads could be converted and managed better. They could even be converted to permanent Knowledge. Slack is an absolute mess. But it works because it is fast, mobile and very much chat oriented so people know it.