Hereoes & Monsters Panel

The Monk was inspired by pen-and-paper-style role playing games. It contrasts from the Barbarian in that while it can deal a great amount of damage, it is significantly more vulnerable.
The Monk emphasizes speed over toughness. The Monk has a variety of combo moves much like the Assassin from Diablo II: Lord of Destruction. The Monk's look and style is a mixture of 13th century Eastern European Monks and traditional Asian Monks.
Skill Changes
The Witch Docto's Spider Totems skill has been revised. In BlizzCon 2008's demo, the skill summoned a totem which spawned a barrage of small spiders that attacked the enemy. They thought the skill was confusing and too messy and cluttered on the screen. The skill has been renamed "Carrion Spiders," which summons a zombie that unleashes few larger sized spiders to attack the target.
The Wizard's Stone Skin spell has also been modified. The development team thought that the stone skin took away from the archetype of the arcane, time manipulating aspect. The current build of the skill is unnamed, but the new skill turns the Wizard into a purple crystallized armor.
Whirlwind has been iterated for the Barbarian. The new demo for Diablo III offers a demon called the Dune Dervish, which has a whirlwind effect that is very animated and surely outdoes the Barbarians of the original build. The new whirlwind is much thicker and more aesthetically pleasing, surrounding the Barbarian in dust and wind.
Changes to Fury
Fury has been through several changes. The original system was a resource where the Barbarian could build up Fury by attacking enemies and then unleashing large damaging blows on foe using the built up Fury. This was a good idea, except the developers found that it was not appealing having to get as many as ten hits in before using the Fury on the target. The newest system still uses the resource, but with endless Fury. This makes for fast paced gameplay but with the caution of using Fury wisely.
Runes, where did they go?
Runes as they exist in Diablo III are used for boosting your character's skills; for example, turning lightning into chain lightning, or making firebomb an explosion as it hits the ground, burning enemies. Jay Wilson states that they aren't going anywhere, but they weren't included in the current playable demo because skill iterations and skill tree changes make the rune system go under significant overhaul.
Monster Classification
The panel also covered monster archetypes for Diablo III and how different monsters are classified.