I think we should definitely keep the forum around. It may not be an active community anymore, but it's still a very rich mine of information regarding FFXII and FFXII IZJS. FF12GM and others may not be around anymore, but they left a lot of knowledge about that game around. And who knows? In a couple years, that information might be viable to a more mainstream audience again if Square Enix goes through with an FFXII HD on PS3 or PS4.
That said, it's true that the community here has moved on to other places. It does, however, still exist. We all still talk to each other, whether it be on facebook, or FFXIV especially, but it's just a core group, very much a shadow of how it was. I haven't even talked to Momina or Allison in months. Hell, all three of our board mods haven't been around in over a month, and I'm no better either. I'm barely around, and I'm a global mod. There just isn't that much to look over.