While thinking about what users should be allowed to on my board I came to the conclusion that it would be a good thing if it was possible to disable only certain BB codes while others remain enabled. That would allow for a more fine-tuned list of allowed features on a board. In the ACP there could be an additional page where you can switch every single BB code on or off. Maybe a good approach to do this would be to make every BB code a "custom" BB code that can be deleted or modified in the ACP.

Yep. and Certianly have a "forum BB Code Config Screen" or it will be too confusing for new IPB users.