Blizzard is, of course, a game company. No one expects them to put on events like WWI and BlizzCon -- they do so to serve the community that's grown up around their games (and, let's be fair, market and advertise their products to the core of their fanbase). And the community loves those events, both hearing about and attending them. Which is why it was a surprise to no one (except maybe Blizzard themselves) that when the ticket sales kicked off Monday morning, it was a nightmare -- the site was hammered by fans trying desperately to buy tickets, the Failoc was a familiar sight, and within a few hours, even Blizzard.com's main site was down.
Everyone could have predicted that there'd be problems like that -- when a fanbase of 11 million tries to buy 12,000 tickets, of course you're going to have technical problems. But Blizzard's mishandling of the situation didn't happen on Monday morning -- anyone can suffer from server outages. It happened over the next two days, days full of frustration, endless page refreshing, and a lack of useful communication from Blizzard about just what was happening.