I really don't know if this is legit because I can't access the beta forums but everyone is treating it like it is.
Blood
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Death Strike now heals you for 30% of the damage you have sustained during the preceding 5 sec (minimum of at least 5% of your maximum health).
Improved Death Strike now also increases the healing granted by Death Strike by 25/50/75%.
Will of the Necropolis now cannot occur more than once every 45 seconds.
Rune Tap now heals you for 15% of your maximum health, down from 20%.
Vampiric Blood now increases the amount of health generated through spells and effects by 25% for 10 sec, down from 35%.
Frost
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Festering Strike is now trained at level 64, down from level 74.
Horn of Winter now has a 45 yards range, up from 30 yards.
Icy Talons no longer increases your maximum runic power.
Howling Blast no longer has a cooldown.
Rime no longer resets the cooldown of Howling Blast for obvious reasons.
Improved Icy Touch is gone.
Runic Power Mastery (Rank 1) *New* - Increases your maximum Runic Power by 10/20/30.
Unholy
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Ebon Plaguebringer now also affects Outbreak.
Ghoul Frenzy is now Dark Transformation - Consume 5 charges of Shadow Infusion on your Ghoul to transform it into a powerful undead monstrosity for 30 sec. The Ghoul's abilities are empowered and take on new functions while the transformation is active. / 1 Unholy, 60 yd range, Instant
Unholy Blight is now a Tier 5 talent, up from Tier 4.
Ravenous Dead has been replaced with Shadow Infusion - When you cast Death Coil, you have a 33/66/100% chance to empower your active Ghoul, increasing its damage dealt by 10% for 30 sec. Stacks up to 5 times.
Resilient Infection implemented - When your diseases are dispelled by an enemy, you have a 50/100% chance to activate a Frost rune if Frost Fever was removed, or an Unholy rune if Blood Plague was removed.
Unholy Command is now a Tier 1 talent, down from Tier 2.
Vicious Strikes renamed Rage of Rivendare no longer increases critical strike chance and critical strike damage bonus. Now Increases the damage of your Plague Strike, Scourge Strike, and Festering Strike abilities by 15/30/45%.
Virulence tooltip clarification - Spells are all Death Knight abilities that are not direct weapon strikes.
Contagion *New* - Increases the damage of your diseases spread via Pestilence by 50/100%.
Unholy - Dark Transformation
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As far as I understand, ghouls now gets charge of Shadow Infusion over the fight and can morph into a powerful undead monstrosity for 30 secs.
Gnaw becomes - Strike an enemy with a smashing attack, dealing 125% of normal melee damage and stunning for 4 sec.
Huddle becomes - Unleash a fortifying roar, reducing all damage taken by 50% for 10 sec.
Claw becomes - Rakes an enemy with deformed claws, dealing 150% of normal damage to the target and up to 2 additional targets.
Leap becomes - Charge an enemy, interrupting spellcasting and immobilizing them for 2 sec.
Unholy got some big
Unholy got some big love.
Blood got a nice change and a small nerf for balancing.
Frost got...uh...things.
GONE
Gone are the days of the DK Blood Tank soloing content...you no longer can heal yourself to full, only 52% of the damage you took in. OH Woe is me!
Now only Paladins and Druids can solo old content... /cry
wut?
DK version of last stand + rune tap or whatever it's called.
uhhhh
*Puts finger in ears*
LALALALALALALALALALALALALA
I will make Frost tanking work in Cata, lawl at blood tanking
LALALALALALALALALALALALALA