I'm a big fan of keeping as many options open as possible and keeping as large a "footprint" as possible for the community. I admit this is kind of counter-intuitive because, honestly, there's a lot to be said for moving the bulk of community discourse to the new Vault, for example. Rolo et. al have done a much better job than I could have ever imagined and I also get a vibe of being able to "speak more freely" when I peruse messages there, which is good. But I think of the other "all the eggs in one basket" places where things didn't turn out well, often because of unforeseen events. The CCG wiki, especially the first incarnation of it. The old CCP, CTP and DLA websites. It's good that archives of a sort have been put up for those last two here and here, respectively, but neither of those are truly complete.
Still, of the new Vault or the BSN forums, I think it's a very safe bet that the BSN forums will probably go down first. Or, worse, be consolidated in some awful "living death" kind of way. I think it's useful to keep things like the CCC going here, for instance, until the rug gets pulled out simply because it's a good way for new people to see that there's still quite a lot of activity in the community. AFAIK, this is one of the first places a person lands after buying the game when they come looking for information. But hopefully any new game purchaser would also learn that there are other options and that this place is definitely...transitory.
The Omnibus download should describe the program that was used to spider through the old Bioware forums and maybe that program will work here. IMO, there have been a lot of advanced contributions (especially in the realm of custom content) that it would be useful to preserve.