How about this… add a new button/link on each extension page that links to a thread on this forum. Clicking the link takes the user to that thread, or creates the thread if it doesn’t exist. The thread will be the “official” support forum for the extension.
Maybe the thread is automatically created when a new extension is published on the EW.
Maybe with a big, fat HELP link on each Extension page, folks will stop using the extension ratings as a support forum.