I think you made a lot of important points here, and I've shared your comment with others as well. Here's what I said:

I think this is comment has some valid critiques of the downsides of this “secret Slack” (which many already know about) relating to Witness discussions regarding community issues such as curation rewards, SBD peg, reward curve, code changes, etc, etc.

https://steemit.com/witness-insight/@lukestokes/re-asbear-re-lukestokes-re-asbear-transparency-is-everything-witness-insight-project-20180514t194657335z#@asbear/re-lukestokes-re-asbear-re-lukestokes-re-asbear-transparency-is-everything-witness-insight-project-20180515t110849800z

I understand the importance of a private channel for responsible disclosure and immediate communication with top block producers to quickly roll out security fixes, but I also think it could be helpful to the overall reputation of STEEM and Steemit to see the important conversations here. My suggestion is we could have a public, read-only communication system (Discord? Telegram?) for the top 100 witnesses and top 50 investors along with Steemit, inc employees to discuss issues which matter to the platform.

IMO, secrecy within open source projects is not healthy. Communication and transparency is always the best approach. As community members read our discussions and post about them on Steemit, it could bring more visibility to what all the witnesses and Steemit, inc are doing to benefit the platform and prepare for long-term growth.