The Tiki developer mailing list is the closest we have to an "official" decision-making body for the Tiki development process.
To post to this list, send your message to:
(It is an image to reduce usage by spammers)
To be able to post to the list, you need to be a member, which you can do here: https://sourceforge.net/projects/tikiwiki/lists/tikiwiki-devel
Once you are a member, you will receive an email with more information.