Class Changes:

Mage

There isn’t much to improve on for the Fire and Frost mage specs in vanilla - they are tightly designed and synergize well with other mages very well. That said, Arcane falls far behind despite having an opportunity to fill its own niche, and the possibility of encouraging the Elemental Mage playstyle.

New Abilities

Arcane Rupture

Learned at Level: 20 Cooldown: 15 sec

Rupture the target for Arcane damage, increasing the damage (and the mana cost) of your Arcane Missiles for a duration. Requires the Arcane talent of the same name.

Arcane Surge

Learned at Level: 32 Cost: 85 mana Cooldown: 8 sec

Increases your casting speed and spell damage for a short duration.

Ritual of Refreshment

Begins a ritual that creates a refreshment table. Raid members can click the table to acquire Conjured Manna Biscuits: a group version of conjured food, in the same vein as the Warlock's Ritual of Souls.

New Polymorph forms

Polymorph: Rodent and Polymorph: Draenei Homunculus join the existing sheep and pig.

New Portals and Teleports

Theramore, Stonard and Alah'Thalas are available as both Teleport and Portal, adding three destinations to your spellbook.

Changes to Class Mechanics

Ignite Threat
When several Fire Mages feed the same Ignite, the threat from the burn is split into equal shares between the Mages sharing it, so no single Mage carries the whole stack.

Changes to Baseline Spells

Arcane Intellect
Mana cost drops sharply at the higher ranks (Rank 3: 520 240, Rank 4: 945 340, Rank 5: 1510 445).

Arcane Brilliance
Available at level 42 as well as level 56, and the level 56 rank costs 1200 mana.

Fireball
Cheaper at every rank, increasingly so at the top (Rank 11: 395 275, Rank 12: 410 295).

Arcane Missiles
The missiles fire on a defined interval, which Accelerated Arcana then speeds up.

Talent Changes

Arcane

Arcane Power
Row 7 capstone: completely reworked
Increases your casting speed while draining a percentage of your maximum mana every second and reducing all mana gain. Fall below 10% maximum mana and you violently combust. A cooldown you have to steer, not just press.

Arcane Instability
Row 6 → Row 5: completely reworked
Your damaging Arcane spells have a chance to erupt, consuming 2% of your base mana to deal more damage.

Resonance Cascade
Row 6, 5 Ranks: new
Your damaging Arcane spells have a chance to duplicate for a share of the damage. It can trigger off itself, and duplicated Arcane Missiles channel in tandem with the original.

Arcane Rupture
Row 3, 1 Rank: new, replaces Arcane Resilience
Grants the Arcane Rupture ability, which empowers your next Arcane Missiles.

Temporal Convergence
Row 4, 3 Ranks: new
Arcane Missiles have a chance to reset the cooldown of Arcane Rupture and refund its base mana cost on the next cast. Once every 15 sec.

Accelerated Arcana
Row 5, 1 Rank: new, replaces Arcane Mind
Increases the casting speed of your Arcane spells, and makes casting-speed effects also speed up your Arcane cooldown recovery and your Arcane Missiles ticks.

Arcane Potency
Row 5, 2 Ranks: new
Increases the critical strike damage bonus of your Arcane spells.

Arcane Impact
Row 3, 3 Ranks: replaces Improved Arcane Explosion
Increases the critical strike chance of all your Arcane spells, not just Arcane Explosion.

Arcane Concentration
Has an 8 sec internal cooldown between procs.

Arcane Meditation
The mana regeneration it allows while casting is tripled while you are below a mana threshold.

Magic Absorption
Row 2 → Row 1, 5 Ranks → 3 Ranks
Returns mana on partial resists as well as full ones, which makes it fire constantly. Internal cooldown 1 sec 2 sec.

Magic Attunement
2 Ranks → 1 Rank
Also allows Amplify Magic and Dampen Magic to be cast on enemies, up to level 62.

Wand Specialization
Also increases your chance to hit with Wands, and gives wand attacks a chance to restore mana.

Arcane Focus
Row 1 → Row 2

Removed: Arcane Mind, Arcane Resilience, Improved Arcane Explosion

Fire

Hot Streak
Row 5, 2 Ranks: new
Fireball and Fire Blast crits have a chance to grant Hot Streak, cutting the cast time of your next Pyroblast. Stacks.

Fire Vulnerability
Row 4, 3 Ranks: replaces Improved Scorch
Fire Blast can now apply the Fire vulnerability debuff as well as Scorch, so you are not locked into Scorch to keep the stack up.

Improved Fire Blast
Also reduces Fire Blast's global cooldown, not just its own cooldown.

Flame Throwing
Also increases the radius of your Blast Wave.

Blast Wave
Moved within Row 5

Removed: Improved Scorch

Frost

Icicles
Row 5, 1 Rank: new
Freezes you in place and launches icicles at the enemy for heavy Frost damage over its duration. Damage taken has a high chance to shatter your icy prison, dealing 30% of your base health to you. Canceling it early does not remove that risk.

Flash Freeze
Row 6, 2 Ranks: new
When a freeze fails because the target is permanently immune (every raid boss), you have a chance to gain Flash Freeze instead, which resets Icicles and speeds it up, so Frost has something to do against immune targets.

Ice Barrier
Also increases your Frost damage while the shield holds, on top of absorbing damage and preventing interrupts.

Shatter
The critical strike bonus against frozen targets scales with the rank you have invested in the talent.

Arctic Reach
Also extends the range of Icicles.

Piercing Ice, Ice Shards, Winter's Chill and Improved Cone of Cold
Repositioned within the tree to make room for Icicles and Flash Freeze. Piercing Ice and Ice Shards swap rows.