Tanks
3-4 (MT + OT for adds/soaking + extras for specific mechanics)
Healers
6-8 (Mix of Paladins, Priests, Shamans, Druids)
DPS
13-16 (Balanced melee/ranged, Warlocks and Mages valuable)
A Balance Druid for Kiggler tanking and a Mage for Krosh tanking are highly recommended for High King Maulgar.