What ho, folks.
Today could be the day.
The magical trademark day.
While there's a good chance Blizzard completely changed their trademark routine recently, there's also the possibility that they're sticking with the trend set by 50% of their expansions. Namely, WotLK and MoP were both filed on July 27 and discovered on August 2.
Cataclysm was a different affair. It was filed on June 26 and discovered on July 1. This was due to the fact that an Australian website held a relevant domain up until then (wowcataclysm.com). As soon as it expired / Blizzard got hold of it, though, they filed the Cataclysm trademark. So had it not been for the immediate urgency to 'get it done' and claim the domain at that time, Cataclysm might also have been a July 28 / August 2 trademark.
The Burning Crusade was such an early expansion, they probably hadn't even figured out their own routines by then. I hesitate to even include it in the statistics.
So yeah. Again. Keep your eyes glued to the trademark website!