Blizzcon is short time away now, nothing else is trademarked that would give a sign of a potential new expansion.
Blizzard has to trademark the name before announcing it
"The Dark Below" got trademarked roughly at same time when other expansions did
New expansion will be announced during Blizzcon
In the past Blizzard mislead people but it was true short time after
So unless Blizard trademarks something before Blizzcon then I think is obvious.
What are your opinions guys?