Rogues never had a decent AoE ability - now they can throw knives. The developers felt like Sap was situationally really good, but it depended on the dungeon. They wanted to make it more useful no matter where you were, so made it affect a wider range of enemies.
Two iconic things for the Rogue class are daggers and poisons, but nobody was using them. With the changes to Windfury and debuffs, hopefully they'll be used more.
Had been THE main tank for a long time in the game. Trying to give players more options for tanks, the developers felt there was a risk that without crushing blows, Protection Warriors would get less and less popular. They looked at the Prot talent tree, and found that Warriors had so many mitigation talents that by the time they had all of them they had no points left to pick up anything "fun". Tried to consolidate talents to give them more points to get cooler, new abilities.
That isn't just for Warriors, but something they want to do with all the classes. They don't want players to say, "By the time I have what I need to have, I can't get anything else."
Tried to give Arms things to use in Battle Stance instead of just staying in Berserker. Overpower and Rend, two important abilities - at least when you first get them - are pretty good again. Bladestorm and Sudden Death are fun abilities - Sudden Death, admitted Street, is maybe a little too fun at the moment. They backed off the penalty on Titan's Grip a bit - they definitely want Fury Warriors out there Dual-Wielding two-handers.
Warlocks have a lot of pets, many they were never using. They want to make it so that you actually have reasons to use them all.
Affliction's rotation was crazy, you were going nuts to keep everything up. Destruction, on the other hand, was spamming Shadowbolt. While they're concerned that Affliction might still be too crazy, Destro is much better now. One of the new abilities, Demonic Circle, lets them teleport around the battlefield during a fight.
They gave them Metamorphosis because really, every Warlock wants to be Illidan.
Biggest cheers (and boos) yet.
Street said that he was really happy with how the overhaul for the Seal/Judgment systems went - they feel great now. The Protection Paladin was always a great Off-Tank, but never a great Main Tank. They want to make them care more about tank gear and put down the Mage sword.
Holy needed heals for movement and groups. They don't want to make them a HoT class, but they do need to give them options while moving.
Retribution needed more DPS without running OOM. Honestly, Street admitted that they were fine when they were in the group with all the buffs, but they were rarely put in that group in the first place.