That, in fact, is exactly what got me thinking that it's possible that BlizzCon itself is bad for the game, for the game community at large, and for the future of the franchise. BlizzCon, by its very nature, is a hype machine. It's where we learn details about the expansion - its name, its features, its setting and goals - before they are even close to being ready for players. People play demos. Developers give talks about the games. In many ways it's very exciting. I've never been myself, but most of my coworkers and a lot of my in-game friends have. So my argument isn't that BlizzCon itself is bad.
But looking over the past year or so, in terms of Warlords of Draenor and player interaction with it, I start to wonder if having the big reveal at the convention does more harm than good, overall. Expectations are set at the convention - looking at the recent player reaction to the news that Karabor and Bladespire wouldn't be capital cities in Draenor, the issue can in part be traced back to the fact that we were told they would be at BlizzCon. Players (like myself) had months to get excited about the idea of Karabor as a capital city. Then, suddenly, we were told (almost as an afterthought) that no, the capitals were moved to Ashran.