Does the C++ core committee have central forums for public discussion of features or is it exclusively a design-by-committee thing with mostly closed-door meetings?
There are also core teams that are closed door. And sub committees, some of which are more welcoming of outsiders than others. In the end though, if you submit a paper the relevant committee will read it and then invite you to come talk about it (at your expense to get there, but they will find a sponsor if needed).