Tried to bold important changes, if I missed something let me know
Druid
Mangle (Cat Form) has been removed. Mangle (Bear Form) remains unchanged.
Nourish has been removed.
Auto-attacks now generate 5 Rage (down from 10.9 Rage).
Shred is now available to all Druids.
Shred no longer requires the Druid to be behind the target.
Mangle now generates 30 Rage, and its cooldown is reduced by Haste.
Bear Form no longer increases Haste and Crit from items by 50%, but instead causes Haste to reduce the global cooldown.
Swiftmend no longer causes Efflorescence.
Rogue
Ambush no longer requires you to be behind the target
Mutilate can now be used with fist weapons or one-handed swords, dealing 137% weapon damage (instead of 200%) when used with those weapons instead of a dagger.
Sinister Strike now deals 188% weapon damage when used with a dagger (instead of 130%).
Hunter
Arcane Shot is no longer available to Marksmanship Hunters.
Aspect of the Hawk has been removed.
Cower has been removed as a pet ability.
Hunter’s Mark has been removed.
Rabid has been removed as a pet ability.
Serpent Sting and Improved Serpent Sting have been removed.
Serpent Spread has been renamed Serpent Sting, and remains a passive for Survival Hunters. It causes Multi-Shot and Arcane Shot to also apply the Serpent Sting poison, which does instant and periodic damage.
Revive Pet and Mend Pet now share one button, which toggles based on whether you have a live pet.
Hyena: Cackling Howl and Serpent: Serpent's Swiftness have been removed
Aimed Shot now deals 20% more damage and no longer interrupts Auto Attacks.
Dismiss Pet now ignores line of sight.
Hunter Pets now have a 1 second global cooldown.
Mage
Arcane Barrage now replaces Fire Blast for Arcane Mages.
Arcane Blast now replaces Frostfire Bolt for Arcane Mages.
Arcane Explosion is now available only to Arcane Mages.
Evocation is now available only to Arcane Mages.
Ice Lance now replaces Fire Blast and is only available to Frost Mages.
Shatter is now available only to Frost Mages.
Presence of Mind is no longer a Talent, and is instead learned by Arcane Mages.
Evanesce is a new Talent available at level 15.
Evanesce: Fade into the nether, avoiding all attacks against you for 3 seconds. This spell may be cast while a cast-time spell is in progress and is not on the global cooldown. Replaces Ice Block. 45-second cooldown. (Ice block? GG)
Arcane Blast's cast time has been increased to 2.25 seconds (up from 2 seconds), and its damage has been increased by 12.5% to compensate.
Arcane Charges now last 15 seconds (up from 10 seconds).
Paladin
Crusader Strike and Hammer of the Righteous no longer apply weakened blowsDenounce's range has increased to 40 yards (up from 30 yards).
Word of Glory now has a 1.5-second cast time (up from instant cast).Sword of Light (Retribution) now also makes
Word of Glory and Eternal Flame instant cast.
Priest
Inner Fire has been removed.
Mind blast now increases magic damage taken by the target for 15 seconds
Shaman
Healing Wave has been removed.
Flametongue Weapon is no longer available to Restoration Shamans
Water Shield is now available only to Restoration Shaman and replaces Lightning Shield.
Earth shock no longer applies weakened blows
Warlock
All of the various Soulburn effects are learned together with Soulburn, instead of at different levels.
Drain Life no longer gains a benefit from Soul Burn.
Drain Soul has been removed.
Drain Life now heals for 30% less than before.
Warrior
Cleave has been removed.
Hamstring is now a passive ability that causes Mortal Strike, Bloodthirst, Revenge, and Raging Blow to also reduce the target’s movement speed by 50% for 15 seconds.
Throw has been removed
Thunder Clap is no longer available to Fury Warriors.
Charge now Roots the target (instead of stunning). The Root effect does not share a Diminishing Return with other Roots.
Warbringer now causes Charge to stun the target for 1.5 sec instead of rooting it.
Warriors lose sunder armor
General Stuff
Agility no longer provides an increased chance to critically strike with melee and ranged attacks or abilities.
There is a new passive, named Critical Strikes, which increases chance to critically strike by 10%.It is learned by all Rogues, all Hunters, Feral and Guardian Druids, Brewmaster and Windwalker Monks, and Enhancement Shamans.
Each point of Agility or Strength now grants 1 Attack Power (down from 2). All other sources of Attack Power now grant half as much as before.
All players now have a 100% chance to hit, 0% chance to be dodged, 3% chance to be parried, and 0% chance to glance, when fighting creatures up to 3 levels higher (bosses included).
Tank specializations receive an additional 3% reduction in chance to be parried, so tank attacks have a 0% chance to be parried vs. creatures up to 3 levels higher.
Attack Power now increases Weapon Damage at a rate of 1 DPS per 3.5 Attack Power (up from 1 DPS per 14 Attack Power).
Weapon Damage values on all weapons have been reduced by 20%.
The amount of Dodge gained per point of Agility has been reduced by 25%.
The amount of Parry gained per point of Strength has been reduced by 25%.
Base Resilience has been reduced to 0%.
Battle Fatigue has been removed. PvP combat no longer reduces the amount of healing received by PvP participants.
Critical Damage and Critical Heals in PvP combat now deal 150% of the normal spell/ability effects (down from 200%).
The amount of health per Stamina has approximately doubled. The curve on this calculation has been smoothed out as well, so the exact amount varies slightly by level.
Maximum mana has been approximately doubled at all levels to keep pace with the expected health from new Stamina values.
All player-cast healing and absorption effects have been increased by approximately 50% in effectiveness. If they heal or absorb a percentage of maximum health, they are instead reduced by 25%. All other noted changes are in terms relative to that.
All Stuns now share the same DR category.
Herbalists can now harvest herbs throughout the game world without hard skill requirements. The yield an Herbalist will be able to harvest from each node is now determined by skill level.
Miners can now harvest mineral nodes in outdoor areas of the game world without hard skill requirements. The yield a Miner will be able to harvest from each node is now determined by skill level.
Healing Potions no longer share a cooldown with other potions, but instead share a 60-second cooldown with Healthstones. The cooldown will not reset until the player leaves combat.