The new Rock Stars got some much needed detail from the Class Panel. Here are a few points.

Developers don’t want talent trees to be pigeonholed into specific roles. Each tree will be functional both roles. This means that there won’t be a tanking tree versus a DPS tree.
Runes have a 10 second separate cooldown. So [...]

So in a nutshell Warriors are going to be Barbarians from Diablo II, Rogues get an AOE, Warlocks can shapeshift, Druids are getting Dire Cat, and Mages will become walking explosions.
Mage

Mage Armor will be reworked to reduce harmful debuff durations, so that’s a more suitable raid armor. Finally.
New ability: Frostfire Bolt. In itself it’s [...]

Priests actually need a lot of love. They’re a class that’s always been hands down meant to be the best healer and yet they’re pretty underrepresented in the end game raiding scene where a resto shaman, paladin, or druid can pick up the slack and outperform with certain spells. Luckily it seems that all around [...]

Alrighty I’m just going to go down the list from what’s most important to me that was disclosed during the 1st day of the WWI about class changes in Wrath of the Lich King. Now mind you none of this is fleshed out much yet but the signs have been pretty loud all over the [...]