I wish this group was somewhere other than slack

A little bit late response, but Watson Workspace from IBM looks promising. It is lacking a couple of functions we have in Slack (most notable the ability to delete messages) but that is coming, they say. It also does not have the same number of apps/integrations. But a cool feature is the summary of what you missed, using Watson AI to detect what is important and not.

that's an interesting application of AI