there's nothing illegal about the forums, which i think cop alot of traffic (people come in and mightn't leave for a while, whereas the resources bit of the site, people come in, download some papers/notes then leave). perhaps a uni could sponsor the forums and put them on there servers, or find another server for them... which you did for a while when the ozlpn.com one crashed a month or so back... split the traffic...
in regards to site improvements, a search function so you could search the entire board, or a particular forum or particular threads for a string of text -- eg if you remembered someone posted something about the '1998 2 unit maths hsc paper' but didnt know if it was in one of the maths forums or in the school forum or somewhere completely different.