What I think I would like here is forum software which is a front-end to NNTP, so that the fora are in reality usenet groups, and can be efficiently accessed with a usenet reader, or via the "friendly" web front-end. This would, I think, provide the best of both worlds, both in terms of ease of access for users, and speedy for developers in keeping up to date with threads in all groups.
Google suggests that such things do exist, but I haven't seen one in practice personally.