All Blizzard expansion names were NEVER trademarked within 8 months of their announcement at Blizzcon. Every single expansion name was trademarked approximately a year or more before it was announced. WotLK was TMed immedietly after WC:3 FT, Cata was TMed half way through WotLK, and MoP was TMed right before Dragon Soul. Stop believing that every time Blizzard TMs a new name now is going to be the next expansion, because it was probably TMed months ago, during MoP and before 5.4.
Blizzard isn't stupid enough to TM the next expansion's name right before Blizzcon. If they did, I'd guarentee you that at least 40% of everyone who's going to Blizzcon now wouldn't, because everyone would pretty much know what to expac from Blizzard's flagship enterprise.