Blizzard became awesome.

[Turducken]

So the next 5 man is going to be awesome, apparently you get to fight "memories" from a list of old bosses. The list so far (according to worldofraids.com) is...

Wrath of the Lich King

    * Raid Bosses
          o Algalon the Observer
          o General Vezax
          o Heigan the Unclean
          o Ignis the Furnace Master
    * Dungeon Bosses
          o Cyanigosa
          o Eck the Ferocious
          o Ingvar the Plunderer

The Burning Crusade

    * Raid Bosses
          o Archimonde
          o Entropius (M'uru)
          o Gruul the Dragonkiller
          o Illidan Stormrage
          o Lady Vashj
          o Prince Malchezaar
    * Dungeon Bosses
          o Priestess Delrissa
          o Warlord Kalithresh

Classic WoW

    * Raid Bosses
          o Chromaggus
          o Emperor Vek'nilash
          o Hakkar
          o Lucifron
          o Onyxia
          o Thunderaan
    * Dungeon Bosses / Quest Targets
          o Edwin VanCleef
          o Herod
          o Hogger
          o Mutanus the Devourer

LOOK AT THE LAST FOUR, THAT'S JUST AWESOME!