The release of WoW TBC Classic made it so both the Horde and Alliance have access to Shamans and Paladin.
During Classic, each class’s healing specialization was powerful, but only being available to one faction made it difficult to compare the two. Now with Blood Elves bringing Paladins to the Horde and Draenei bringing Shamans to the Alliance, a whole new world of compositions are available.
For healers, this will mean more diversification as Alliance raids look to bring in numerous Restoration Shamans and Horde groups look to grab one or two Holy Paladins.
Shamans are the strongest raid healers in the game and provide massive amounts of utility with their totems.
Chain Heal is the strongest ability in the game for healing multiple people in your raid at the same time. Meanwhile Shamans provide group utility through totems like Poison Cleansing, Disease Cleansing, Stoneskin, and Tremor totems.
Balanced raid compositions will have two to four Resto Shamans depending on how many Enhancement or Elemental Shamans the group wants to bring. Regardless of spec, you’ll want five Shamans total in your 25-man raid, one for each group.
Priest is the only class in the game that has two separate talent trees dedicated to healing specializations, and it shows.
The class provides important raid buffs like Prayer of Spirit and Power Word: Fortitude, and its utility extends to abilities like Power Word: Shield, Power Infusion, and Fear Ward. Priests are strong single-target healers, but they can also keep a raid topped off as well. You likely don’t want more than two Priests in a balanced composition just because of all the other party/raid buffs and utility various other classes provide.
Holy Paladins are the best tank healers in the game. You likely don’t want more than one in your raid, but the role they fill is critical. What they lack in AoE healing, Holy Paladins make up for in pure, unadulterated single-target tank healing.
At the very least, one Holy Paladin in a raid will give all casters Improved Blessing of Wisdom to boost overall raid mana. They also provide utility with abilities like Blessing of Freedom.
Restoration Druid was an important class to have in Classic specifically for giving the raid Mark of the Wild and debuffing bosses with Faire Fire. But their throughput was severely hindered by Classic’s buff cap that made it suboptimal for them to hit players with healing-over-time effects (HOTs).
In TBC, you’ll want to bring Druids for the same buffs and utility that made them necessary in Classic, but their viability will be increased significantly by changes to the buff cap situation that make it perfectly fine for them to roll HOTs on tanks and other players.
You will want to run one Resto Druid for Improved Mark of the Wild, but probably not more than that because of how much more powerful other classes are.