I love this idea.  

I think in order to make it work you will need to archive the main board though, because people will continue throwing everything in there out of habit. You may want to do something like archive old stuff by year anyway, just to keep things manageable and improve performance.

Having different forums would also help encourage more participation by newbies and people from the smaller conferences/programs that we don't hear from as much.  If there are forums set up specifically for them, I think they'd be more inclined to comment.