Oh, I always though PAX would have a brand new demo. Now that I think of it, does not make much sense (in a realistic way ).
Then again, they had I think 2 weeks in between Gamescon & PAX. Maybe they decided to be fancy and actually do it. I mean those 3 races already are in-game, just need to set up level and content restriction.
I don't think they're that far yet with the whole game. Plus two weeks isn't enough time to make a demo. Considering balancing, debugging, leaving content out, leaving professions out, making sure the dialogues dont contain any information that is not supposed to be revealed yet, uploading servers, installing computers, making sure the demo runs smooth on all systems. Quality assurance takes alot of time I would say. ;P