
Considering I play the class on the live realms, I just had to see if the Death Knight revamp was implemented. Much to my enjoyment it seems to at least be partially implemented, including updated talent trees and some ability changes, as well as the new rune system. Unfortunately those playable for the event only had 31 talent points (pre-made bug probably). Death Knights also seem to be the most implemented aside from the four released previews.
Presences
The presences, as expected, have been revamped now that Blood is the tanking tree and the others are for DPS. I was sad to see that the flavor of having a presence heal you based on the damage you deal is going away, but perhaps these new presences fit in more with their respective trees.
Blood Presence - This is now the tanking presence, and from what I could tell is exactly
the same as the current Frost Presence.
Frost Presence - Now increases damage and Runic Power generation by 10%.
Unholy Presence - Now increases attack speed and rune regeneration by 10%
movement speed by 15%.
Abilities
There may have been other minor ability changes, but I wanted to focus more on the talents in the time I was on the Death Knight.
Obliterate - No longer removes diseases. This might be a bug due to the tooltip still saying it does. But with the Annihilation change...
Rune Strike - Now an instant attack instead of next melee. Still requires a dodge or parry to use.
Death and Decay - Now only costs 1 Unholy rune. Used to cost 1 Blood, 1 Frost and 1 Unholy.
Talents
Blood
Subversion has been removed completely. The crit bonuses provided by it will be greatly missed.
Blood-Caked Blade - Moved over from Unholy and is now a tier-3 talent.
Bone Shield - Moved over from Unholy and is now a tier-3 talent.
Toughness - Moved over from Frost and is now a tier-4 talent.
Hemorrhagic Fever - New tier-5 talent that causes Blood Boil to reduce physical damage dealt by 10%.
Improved Blood Presence - Now causes you to become crit immune at 2/2.
Will of the Necropolis - Now also generates a Blood Rune and resets the cooldown on Rune Tap when it triggers.
Blood Parasite - New tier-8 talent, chance to spawn a Bloodworm with attacks. It will attack a target until it explodes, healing nearby allies.
Sanguine Fortitude - New tier-8 talent, 3 ranks, improves Icebound Fortitude reduction by 10% per rank(?) and at max rank makes it cost no runic power(?). Note: Couldn't spec this far to confirm that.
Heart Strike - Now hits 3 targets.
Blood Swarm - New tier-10 talent, when you use Plague Strike on targets with Blood Plague it has a chance to make Blood Boil not cost a rune.
Dancing Rune Weapon - Now also increases parry chance by 20% while it's active.
Frost
Unbreakable Armor - Removed.
Runic Empowerment - New tier-1 talent, 5 ranks, has an 8/16/24/32/40% chance to active a random fully depleted rune whenever you use Death Coil, Frost Strike or Rune Strike.
Annihilation - Now increases Obliterate damage by 10% per rank (up to 30%). No longer states that it prevents Obliterate from removing diseases.
Pillar of Frost - New tier-5 talent, 1 Frost; 1 min cooldown, increases strength by 20% and provides immunity to "external movement" like knockbacks for 20 seconds.
Brittle Bones - New tier-5 talent, 2 ranks, increases strength by 2/4% and causes targets affected by Frost Fever to take 2/4% more physical damage.
Rime - Now also causes Icy Touch to not consume a rune when it procs.
Improved Frost Presence - Increases the bonus damage of Frost Presence by 2/5%.
Might of the Frozen Wastes - New tier-10 talent that gives you a chance to generate Runic Power with melee swings when using a two-handed weapon.
Unholy
Epidemic - Moved to tier-1, increased to 5 ranks.
Unholy Frenzy - New tier-3 talent, essentially Hysteria. Increases melee and ranged haste by 10% instead of increasing damage.
Morbidity - Moved to tier-4.
Improved Unholy Presence - Causes Unholy Presence to grant an additional 2/0% "haste". Note: Obviously bugged and intended to be 2/5%.
Scourge Strike - Now only costs 1 Unholy rune.
Sudden Doom - Moved over to tier-10 from Blood. No longer instantly procs Death Coil, just causes it to cost no Runic Power.

The only other class I found that had even remotely significant talent changes was the Warrior class.
Abilities
These are level 80 values where I mention numbers.
Heroic Strike - Now an instant attack that costs 10 rage. It consumes up to an additional 20 rage to deal extra damage. Almost an exact replica of Execute, which seems odd.
Cleave - Now an instant attack similar to Heroic Strike. Hits target and nearest ally.
Thunder Clap - Base slow increased to 20%.
Battle Shout - Now generates 10 rage and increases strength and agility of party members by 155. 1 min cooldown, 2 min duration (shared with Commanding Shout).
Commanding Shout - Now generates 10 rage and increases party / raid member stamina by 165. 1 min cooldown, 2 min duration (shared with Battle Shout).
Demoralizing Shout - Now reduces physical damage caused by 10% for 30 sec.
Sunder Armor - Now only stacks 3 times.
Whirlwind hits unlimited targets for 54% weapon damage.
Talents
Arms
Weapon spec talents have been removed.
Impale - Now a tier-2 talent.
Deep Wounds - Now a tier-2 talent.
Wrecking Crew - Now a tier-5 talent.
Disarming Glare - New tier-6 talent, 2 ranks, Disarm also causes the target to cower in fear.
Blitz - New tier-7 talent, 2 ranks, causes your Charge to stun 1/2 additional targets.
Improved Slam - Now a tier-10 talent.
Fury
Cruelty - Redesigned. Now increases crit chance of Victory Rush, Slam and Bloodthirst by 5/10%.
Enrage - Now a tier-2 talent.
Impending Victory - New tier-2 talent, 2 ranks, Heroic Strike, Slam and Bloodthirst have a chance to allow the use of Victory Rush.
Dual Wield Specialization - Now a tier-3 talent.
Precision - Now a tier-3 talent.
Relentless Bloodrage - New tier-3 talent, 2 ranks, Increases the duration of Bloodrage. Note: Tooltip was bugged but duration at 2/2 was 40.2 sec.
Fury in the Blood - New tier-4 talent, 5 ranks, increases damage caused by 2% per rank while Bloodrage is active.
Improved Berserker Rage - Now a tier-10 talent.
Single-Minded Fury - New tier-11 talent, 1 rank, increases damage by 20% when dual wielding one-handed weapons and causes Cleave and Slam to hit with both weapons.
Protection
Improved Defensive Stance - Now a tier-2 talent.
One-Handed Weapon Specialization - Now a tier-4 talent.
Critical Block - Now a tier-5 talent.
Sweep and Clear - New tier-6 talent, 3 ranks, damaging abilities generate 1 rage for every extra target they hit, up to a maximum amount of rage.
Safeguard - Now also provides crit immunity at 2/2.
Improved Disciplines - Now a tier-9 talent.
Alright, that's it for the classes I actually played. I did log on some others to see if their talents were implemented, so here's some general changes.
Miscellaneous Changes

Talent changes were not implemented. Talents still mentioned reducing the cost of mana, etc.
Max focus is 100 and seems to regenerate at about the same rate as energy does for Rogues.
You start with a pet and Arcane Shot which costs 45 focus. You cannot control your pet until level 10.
Steady Shot is learned at level 3 and generates 9 focus each time it's used.
Mongoose Bite was not in the spellbook, so I assume it's been removed.

Talent changes were not implemented.
Arcane Missiles is now triggered by any of your damaging spell casts. It costs no mana, but is still channeled.

Only two talent changes seemed to be implemented:
Vindication now reduces physical damage dealt by 10%.
Swift Retribution now causes your auras to increase party / raid melee and ranged haste by 7/14/20%. Probably doesn't stack with Windfury or Improved Icy Talons.
Crusader Strike is now baseline, as announced.
Divine Storm hits unlimited targets.
Blessing of Might now increases attack power by 10% and grants mp5
Divine Intervention appears to have been removed.
Source: http://www.worldofraids.com/
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