Not given this issue much thought yet but I wonder whether having admin control panels are neccessary, certainly in their current form. When creating a blog post or forum post, there’s no more logical place to do it than on the blog or the forum itself. Why does a totally separate interface exist for creating forums or creating categories? If you want to edit a forum topic, you can do it right there. But if you want to edit a forum, you need to log in somewhere else and do it in an interface which is totally different.
I presume the main reason is for security – if you left your computer logged on your website, someone could do limited damage before logging in again. A separate interface may not be the only solution. The software can be designed in such a way when a user would do an action which makes large changes it prompts the user to re-enter their password.
Putting content and user control back into the main interface may give a better workflow. Of course there’s going to be general settings such as board name, e-mail configuration, etc. These could exist as part of the main script as an additional page; it doesn’t need to necessarily be a totally separate script.