Balance Changes

Improved Counterability Unarmored Light Medium Heavy Fortified Hero
Normal 100% 150% 100% 100% 50% 100%
Piercing 150% 75% 100% 150% 35% 50%
Siege 150% 50% 100% 100% 150% 50%
Magic 75% 100% 200% 100% 50% 50%
Hero 100% 100% 100% 100% 50% 100%

You can find further information related to armor and damage types on our web site at http://www.battle.net/war3/basics/armorandweapontypes.shtml.

Spellcaster Rebalance

Most spellcasters (Sorceress, Priest, Shaman, Witch Doctor, Necromancer, Banshee, Druid of the Talon) have been re-balanced.
In general, units with piercing damage rip up spellcasters, while basic melee units, such as Ghouls or Footmen, are weak against spellcasters.
The specific changes to the units in question are:
They have a new armor type, unarmored, which takes bonus damage from siege and piercing attacks.
They also have a new damage type, magic, which does reduced damage to fortified and hero armor, but does bonus damage against medium armor.
They had their damage adjusted, typically downwards.
They no longer gain damage as they go up in level, and gain less hitpoints as they go up in level (but start with more hitpoints when initially built)
Many autocast buffs and debuff costs reduced.
Casters, including Dryads, have had their mana regeneration rates boosted by 30%.

Hero Damage

Heroes now have an aptly named hero damage type.
It deals 100% damage to everything except fortified armor, to which it deals 50% damage.
Hero damage was added so that heroes no longer strongly counter ranged units such as Archers and Crypt Fiends.

Advanced Structures

Most advanced technology structures had their build times reduced.
This reduction ranged from 20 seconds for especially underused structures, to 10 seconds for less underused structures.
For instance, the Slaughterhouse builds 20 seconds faster now, while the Arcane Sanctum build time was only reduced 10 seconds.

Humans

Flares now cost 75/25 to research, down from 100/50.
Inner Fire cost increased to 35, from 25.
Slow cost reduced to 40 from 50.
Slow duration vs heroes reduced to 10 seconds from 20 seconds.
Thunderclap debuff is 50% at all levels, and lasts 5/3 at all levels.

Undead

Curse now causes a 33% chance to miss, up from 25%.
Curse now lasts 2 minutes, up from 1 minute.
Curse cost reduced to 40 mana from 50.
Web lasts 12 seconds, down from 20 seconds, and has a cooldown of 12 seconds, down from 20 seconds.
Carrion Swarm max damage increased to 375/700/1000 from 300/550/800.
Carrion Swarm no longer hits wards.
Boneyard cost reduced to 250/100 from 350/125.
Acolytes now have 220 health, up from 180.
Necropolis cost reduced to 300 gold, down from 350 gold.
Black Citadel now has 2000 hitpoints, down from 2300.
Halls of the Dead now has 1750 hitpoints, down from 2000.

Orcs

Bloodlust cost reduced from 50 mana to 40 mana.
Raiders now have light armor instead of heavy armor.
Raider Ensnare lasts 12 seconds, down from 20 seconds, and has a cooldown of 12 seconds, down from 20 seconds.
Bladestorm cooldown reduced to 3 minutes, down from 4 minutes.

Night Elves

Cyclone duration on units increased to 15 from 10.
Faerie Fire cost reduced to 35 from 75.
Chimaera Roost cost reduced to 230/70 from 280/100.
Ancients temporarily lose their fortified armor when they uproot, becoming medium armor units.
Dryads now have the unarmored armor type. This change was made to further specialize
Dryads as melee killers, but allow piercing damage units, such as Crypt Fiends and Archers, to counter them more effectively.
Dryad hitpoints increased to 435 from 380.

Other

All basic siege units (Mortar Teams, Catapults, etc.) have had their night sight increased to 1100 from 1000.

Creeps

Creep-cast Polymorph duration reduced to 25.
Creep autocast Heal heals 12 hp a cast not 15.
Lightning Lizards, Thunder Lizards and Storm Wyrms no longer friendly fire - their attacks only hit hostile targets.
Lightning Lizard damage reduced from 1d8 + 16 to 1d8 + 14.
Thunder Lizard damage reduced from 1d11+30 to 1d8+26.
Centaur Impaler hitpoints reduced to 350 from 450.

Items

Anhk of Reincarnation is now a level 7 item.
Potion of Restoration now heals 500 health and 200 mana, rather than fully replenishing ahero's health and mana.
Scroll of Restoration now heals 300 health and 150 mana, rather than fully replenishing all targets health and mana.
Tome of Experience is now a level 5 item.
Scroll of Protection cost reduced to 150.