On the site for one of my Guilds, we switched to using
Discourse. I'm a convert now. It just flows so smoothly, and actually fits how I use DC actually... I never look at the forum look, unless I'm posting, which makes it more involved to post than it needs to be. I look at things from an unread threads perspective rather than the breakdown that we have here.
Discourse works exactly like that, with the added advantage of the fact that you can just post, and assign it to where it needs to go, without having to go to that area first. Tags/Categories take the place of the subcategories.
I just know that we'd discussed it, so I just wanted to chime in after practical use.
The site, if you're interested is
http://forum.guildm8s.com.
The short of it is, I really dig it now. Not sure how it is from the admin side, but as the user experience, it works well.