I would definitely love to see automated forum posts, one thread per app, that get new posts when the app is updated. One could set up RSS feeds for apps they use, or these could be used to generate an "autoupdater" sort of setup if desired: Make a list of .PND's currently on the system, compare to RSS feed of those threads, provide download link+changes/description if there's new posts.
Absolutely no for discussion in the thread, though. That quickly bogs down otherwise useful "utility" threads like this. Could well have a forum elsewhere for discussion of apps, but update threads should be read only. Prevent thread bumping when there's no update as well.