Everything currently against them aside, look at these Death Knight abilities/talents.
Lichborne
Requires Runic Power
Instant 5 min cooldown
Draw upon unholy energy to become undead for 30 sec. While undead, you are immune to Charm, Fear and Sleep effects, and your horrifying visage causes melee attacks to have an additional 25% chance to miss you.
Sorry Warlocks and Priests. And for Paladins and Priests that think they will take advantage of an undead classed character...
Anti-Magic Zone Rank 1
1 Unholy
Instant 2 min cooldown
Places a large, stationary Anti-Magic Zone that reduces spell damage done to party members inside it by 75%. The Anti-Magic Zone lasts for 30 sec or until it absorbs 10000 spell damage.
Anti-Magic Shell Rank 1
1 Unholy
Instant 15 sec cooldown
Surrounds the Death Knight in an Anti-Magic Shell, absorbing 75% of the damage dealt by harmful spells. Damage absorbed by Anti-Magic Shell energizes the Death Knight with additional runic power. Lasts 3 sec.
Ouch...
Degeneration Rank 1
1 Unholy 5 yd range
Instant
Requires Melee Weapon
Instantly attack the target, dealing 60% weapon damage and inflicting a disease dealing 56 over 21 sec. Any existing heal over time spells on the target become corrupted, dramatically increasing the damage done by the disease and removing the healing effect.
Potential downfall of Druids?
Bone Armor
1 Unholy
Instant 30 sec cooldown
The Death Knight is surrounded by 4 whirling bones. While at least 1 bone remains, Ghe:she; takes 40% less damage from all sources and deals 2% more damage with all attacks, spells and abilities. Each spell or attack that lands consumes 1 bone. Lasts 5 min.
Rune of Spellbreaking
5 sec cast
Requires Two-Handed Axes, Two-Handed Maces, Polearms, Two-Handed Swords, Staves
Affixes your two-handed rune weapon with a rune that deflects 5% of all spell damage. Modifying your rune weapon requires a Rune Forge in Ebon Hold.
Okay, can we please stop now?
Mind Freeze Rank 1
1 Frost 5 yd range
Instant 10 sec cooldown
Strike the target's mind with cold, dealing 100 Frost Damage modified by attack power and interrupting spellcasting while also preventing any spell in that school from being cast for 4 sec.
Strangulate Rank 1
1 Blood 30 yd range
Instant 30 sec cooldown
Strangulates an enemy, silencing them for a maximum of 5 sec, and deals up to 175 Shadow damage modified by attack power at the end of the effect.
I guess not...
But hey, if it will make you feel better, Rogues are getting screwed almost as badly.
On a Pale Horse Rank 2
You become as hard to stop as death itself. The duration of all Stun and Fear effects used against you is reduced by 20%, and your mounted speed is increased by 20%. This does not stack with other movement speed increasing effects.
Icebound Fortitude
1 Frost
Instant 1 min cooldown
The Death Knight freezes Ghis:her; blood to become immune to Stun effects and reduce all damage by 50% for 12 sec. Does not remove existing Stun effects.
Yeah, I know what my new main is going to be come WotLK.
I feel bad for ya casters, and i'm sorry to say, but you're done. It's over. You're finished. Pack it in. Game over man. Game over...
Subject: Death Knights. Lets have a look at them 
