So BlizzCon 2010 is creeping up on us slowly and it's still not clear what this years event will focus on. After all, in the past we had some major events like the announcement of Cataclysm, Diablo III and Starcraft 2.
So...it's still kind-of unknown what we might be able to expect this year. However, looking at every Blizzard games track-record gives us at least a little room for speculation.
Diablo III: It was announced during GamesCom that Diablo III might be delayed until 2012 (2011 was the assumed release year).The game simply isn't as far along as most people seem to believe. However, based on the current published classes, BlizzCon might see the announcement of the Hunter/Ranger class (since it's the most obvious niche to fill). This seems very likely.
Starcraft 2: Work on Heart of the Swarm only just began a few weeks back so it seems unlikely that they might have stuff to show. Blizzard also said it wouldn't be released until well over a year after SC 2. Since the game is still fairly new on the market, it seems unlikely that SC 2 will see any major announcements. Maybe some new Battle.net features or tournaments.
Warcraft: Nothing is known about the classic Warcraft franchise. However, with Starcraft 2 already released it seems unlikely that Blizzard would release another RTS game or even announce it for years to come. Maybe a completely different game in the Warcraft universe...but that too seems rather unlikely. I assume the Warcraft franchise will remain solely in the hands of WoW for now.
World of Warcraft: End of October seemed a likely candidate for a Cataclysm release until the complete talent-makeover basically nullified all previous testing efforts. However, we still might see the release of patch 4.0 sometime around BlizzCon, although I don't see how this could be included as part of the major event. Maybe Blizzard will use BlizzCon as a platform to show of the new 4.0 cinematic for the first time. I'm also very sure that Blizzard will announce a Cataclysm release date either during or shortly before BlizzCon.
Next-Gen MMO (aka. Project Titan): Highly unlikely anything about this project will be published for a while. Not until WoW is on a decline. Anything else would just be self-sabotage.
Ergo, the most likely announcements for BlizzCon 2010 are imo:
-Ranger class for Diablo III
-Cataclysm release date
-potentially a first-look at Heart of the Swarm
Yet even if all those above are true, it seems a little lack-luster compared to the previous years. I know even Blizzard can't unleash a bomb-shell every BlizzCon but I'd have hoped they'd at least try to retain a certain standard.
Anyway, feel free to participate in BlizzCon 2010 speculation.