Originally set for the 20th, Blizzard feels that the proximity to the US holiday of Thanksgiving would have been a problem for supporting the event. Therefore, they have delayed the start of the season until they will have more resources available.
Salthem also announced that the European launch of Arena Season 3 is delayed until November 28th for the same reasons.
It's unfortunate that Blizzard didn't think of the holiday ahead of time, but I think that this is the right decision.
What do you think? Did they do the right thing by delaying Season 3?