What better time to make a game trailer on a pre-aplha.
ROFL.
Of course there is no better time, because there is only ONE Quakecon each year, and to have the chance to not only be the first non-id game ever to be revealed at Quakecon but also to open Quakecon with it. And you have to reveal with moving pictures (i.e: Trailer) to get enough inetrest. It was also the perfect place to have people playtest it.
That's why it got covered on so many gaming sites. And Quakecon wasn't postponed just to have the game in a more recent state,
But I can understand that many people don't understand that.
PS: Have you seen the very first Borderlands 1 screenshots that came out 2007. A lot looked so bland and boring. But they released them early to hype the game. Trust me, these companies know what they are doing.