I must say that I had expected more from the 'trailer' on the website but I'm excited. StarCraft and Diablo have been ignored way too long by Blizzard now. I hope that Diablo will get a sequel as well, though it will be a long run since it's probably gonna take a while until StarCraft II is released.
Cinematics alone don't make a good game. I prefer the gameplay and story to be good and have mediocre cut scenes rather than good cinematics and bad gameplay and no story. But yes, in addition to a great game, cinematics in Blizzard's style would be nice.