(Now-defunct) Westwood games were designed to make people want to play them and to make people have a good, often silly time while doing so. Blizzard games seem designed to make you not want to not play. Starcraft, Diablo II, World of Warcraft... one of the greatest things that they have in common is that they have their own extremely obsessive cultures. (They're also, you know, very well-designed games.) They're the type of games that can cause people to die of exhaustion in an internet café. I can imagine this scenario in which the Westwood employee goes home happy because a gamer had a good time with their product, and the Blizzard employee goes home happy because a gamer had such a good time with their product that they will call in sick tomorrow so that they can play more.
That's all imagination, but it almost seems plausible. World of Warcraft just feels like it's a game that demands more and more of you. It's designed to be addictive. That's not to say that there aren't a lot of addictive games... but Blizzard knows better than anyone how to craft games that are addictive right from the drawing board, rather than just creating something that it's so fun that you don't want to stop playing. It's now clear to me that they have subversive plans of worldwide mind control.