I don't really see Titan being announced this year, I can definitely see it appearing next year, but I'm gonna guess it'll skip this year over. They already have plenty to show us, next year there won't be a WoW or Diablo III expansion to announce, so they'll sell the show with Titan and the next SC II expansion. That's my prediction at least, I could of course be terribly off.
Definitly the next expansion, hell maybe even a fully playable demo, considering they wanna push faster, and i dont really see MoP last that long.
It baffles me that people are assuming that there will be no Blizzcon 2013. Whether this guess is from the data we received from the conference call (which isn't enough to cancel blizzcon), or whether its just people being cynical in their self-inflated mindset that "Blizzard is dying", I have no idea.
Like others have said, Blizzcon 2013 will be HUGE. Every "other year" at Blizzcon is huge. 2009 was pretty big, 2010 was kinda low-key. 2011 was HUGE with features from all three games and 2012 was so low-key they cancelled it.
Blizzcon 2013 will feature a new Wow expansion announcement, likely Diablo 3 Expansion. news on Blizzard All-stars, preview for the Legacy of the Void and perhaps even a preview at Titan and the Warcraft movie.
I'm willing to be Blizzcon 2013 will blow past Blizzcons out of the water, considering last year they didn't have any at all.
Gonna be even harder than ever to get Blizzcon tickets this year. Demand is so huge they sell out in seconds now. I still remember the very first Blizzcon tickets were available for a week. Second one tickets were available for a couple of days. Now they sell out so fast most people just end up staring at a crashing website or a 5000 person queue.