Fair. My point is that you have a fairly unique set of requirements, such that there is a tradeoff in tooling to cater to part-time/open contributors vs. a core/extended team doing active engineering.

You bring up some reasonable points, even though I disagree with asking teams to not use Slack (as I vastly prefer it to IRC these days, but I am focused on open source collaboration with active engineering teams). I think a compromise would be for teams that want open contribution or a chat support channel to turn on Slack's IRC gateway.