Blizzard has released class previews for the barbarian and wizard, outlining how each will be changed in the upcoming 1.0.4 patch.

The primary goal of 1.0.4 is to improve build diversity, meaning the team at Blizzard is taking a long hard look at some of the most unpopular skills for each class, figuring out why they aren't being used in your builds, and then seeing how they can be improved - either by redesigning how they work or just giving them a considerable buff.

You'll find details on the barbarian here, and the wizard here.

Look out for class previews for the Monk, Demon Hunter and Witch Doctor soon.