Well ... a lot of this kind of discussion comes up informally, embedded in other e-mail.
I don't find it practical to say "let's run to the bboard before inserting any comments about adding features to X while discussing such-and-such topic in private".
Also, how about ideas spawned by a single person? Do I have to post every idea I have before solidifying it into a solid proposal? Yuk. Count me out of that process!
And I think in many cases we're better served by having folks put up a target for comment that's organized logically and reasonably well-written.
What I want to avoid is design lock-in and certainly implementation without public feedback. If we meet that goal (and we haven't always in the past) I really don't see any room for complaint. If the design of the portal package written by OF had been presented before implementation I don't think people would be complaining.