I very much like the "Enable Album Creation" option for Photo Gallery Container.   Would be nice to have the same ability for the Discussion Container to, with a checkbox, disable creation of new boards.
I can't otherwise see how to let users create topics without them also having the ability to create boards.
I want them to only be able to create topics.
What I did for photos is:
on the photos "default" page, I placed the gallery web part and unchecked "Enable Album Creation"...users can upload photos but not create albums on a whim.
on a photos "admin" page, I placed the same web part but left "Enable Album Creation" checked, and of course, secured this page to the role(s) that should manage public albums.