It is a good idea to have one per group. Druids can fill the roll of decurser and healer, and can fill in for both roles. Rogues, usually take a lot of seven souls gold damage in fights so they should not be put in a main or alternate tank group.

Recently PC Gamer UK releases some new information about the upcoming World of Warcraft: Cataclysm expansion. Such as raids, mechanics and something more, there are rumors about the major plotlines in Cataclysm, as well as details about the group and raid instances that will be available at launch. There are some details follow as:

Inner-Horde relations: After assuming command of the Horde, Garrosh labels Cairne a traitor and executes the Tauren Leader.

However, this does not seem to be the end of his involvement in Cataclysm and his seeming demise is linked to the greener, lusher Desolace. Garrosh will throw out most of the Blood Elves and Forsaken from Orgrimmar.

War-chief of the Horde: Thrall will become the next Guardian of Tirisfal. However, Thrall will merely 'leave Garrosh in charge' though this does not stop Garrosh from declaring war on the Alliance and fortifying Horde outposts and cities.