MoP Release: 2 world bosses October 2nd: 6 bosses from Mogu'shan Vaults October 9th: Mogu'shan Vaults heroic/LFR October 30th: Terrace of Endless Spring and Heart of Fear totaling 10 bosses November 6th: Terrace of Endless Spring and Heart of Fear heroic/LFR
Total number of bosses: 18 (16 from raid instances and the 2 world bosses)