We're not really worried about the players who don't use the forums. We're worried about the players who do. When an MMO has several million subscribers, that minority of players who frequent the forums can still number in the millions. That's a lot of players and almost all of those players want server specific forums.
I've been wanting to start posting more to try and make some friends but it's impossible to develop a rapport with people when all the threads apply to virtually everyone in the game, no matter where they are or what server the play on. The Guild Hall is a joke. Almost no one puts the server in the thread title, making the job of looking for a guild on my server a lesson in futility. And wanting to set-up a group in advance for a few flashpoint runs later in the day? Forget it.
The simple fact is, this is the first MMO I've ever played (and I've tried a ton of them) that has not had server forums and the games community is sorely lacking because of it.