Most of your points here revolve around supporting arguments for adequately splitting up communication into sub-channels that aren't flooded with thousands of people giving input, but that still doesn't mean it's a case for hosting those conversations behind closed doors, by invite only, and without any logs.

We don't send every reply to every ticket in the issue tracker to one single mailing list where everyone is required to sift through it to find the discussions relevant to them (and I don't mean the firehose notifications here, that's just a secondary feature for convenience). When you adequately split up discussion boards and mailing lists into sub-topics that evenly split the community up by interest (and the P2s already are), you can host very useful and controlled discussions completely in the public eye, where absolutely anyone that wants to be involved can speak their mind even if they aren't writing the code themselves. Trac is actually the perfect example of that.

Sometimes conversations become heated, and trail off-topic, as they do all the time on Trac and the forums, but proper moderation is the key, and you can still do that on mailing lists, and even P2s. When you look at the infamous LKML, completely public, with over 500 messages per day on a single mailing list, but consider that this is exactly where and how the Linux kernel is designed and developed (and even where you submit patches too), it's actually pathetic to see WordPress denying the public access to spark new conversations or give feedback on one simple and small core feature plugin. In order for me to make one comment on something related to one feature I'm concerned about, WordPress now expects me to dive entirely in and become a full-time contributor to that feature or I'm not allowed to even join those meetings. I have to be a member of a team now. WordPress really has forgotten what it means to be an open source project.

I wholeheartedly agree with Marko's views on open communication:
http://markoheijnen.com/open-source-and-my-opinion-on-it/

As for "design-by-committee", you're right, you can't, but just because everyone can comment on some new feature doesn't mean you don't still have leadership. a democracy, or some kind of equal representation involved in making timely final decisions. It just means that the project has a chance to get a well rounded idea about where the *entire* community stands on something even if you can't address everything and everyone. The most important part is that everyone is given the chance to speak and be heard.

You can't do any of that on Skype.