By now I think it is apparent that Jason is solely working on Blizzard's secret new project, commonly referred to as "Titan". Otherwise we would have seen a cue or two by him on the new WoW expansion set.
I have played a lot of blizzard's games : warcraft II, III ; Diablo II and III, Starcraft and Sartcraft II.
This game is not a secret project, it's just a new game.
Myself i think that the best game of blizzard is Warcraft: Orcs and Humans, and after Warcraft II: Tides of Darkness. I think that drawing, music, history were finest, more elaborated. The old team was more serious.
However Global Staffing Team of Blizzard Entertainment has clearly not the same point of view. I have heard a lot of interviews.
But i hope for Blizzard that my opinion is a mistake.