With wow's next xpac probably going to be announced (I say that because cata released dec 2010, and blizzcon 2011 showed a very far advanced xpac and will be even more so since mop released oct, then blizzcon 2013 sounds right for an xpac announcement)
A d3 xpac announcement prob, not as much details as the wow xpac will have, but it'll be general idea's poss new class etc.
MAYBE a sc2 xpac? Prob not since heart of the swarm will release only 7 months prior..They'll prob save that for blizzcon 2014.
And my guess, will be the bombshell. Titan. Titan will finally be announced with huge details on this MMO. If not blizzcon 2014 it'll be announced..But I don't think that leaked q4 2013 is an accurate release at all. I think it'll be announced blizzcon 2013 and released end of the year 2014 most likely. Because blizz is slow. Titan will be all the corrected mistakes of wow.
I'm guessing it may start with huge features wow has, like lfd and stuff like that. With an amazing engine and such.
I think there will be a delay in titan because they want it to have the best engine possible and not an older engine. They'll want it with the newest tech of it's time.
They say it's a real next generation MMO..I hope so.