As some have said earlier, the reason why Druid is pretty much irreplaceable (almost) in raid squads is the fact that they can provide 25 Might, class-specific offensive buffs, as well as healing to all 10 players, among other things. These are very important squad considerations condensed into a single player (i.e. very efficient). This is so good because: Grace of the Land is 10-target MightSpirit bonuses are 10-targetUnlike 5-target based boon-share, 5-target healing will leak to the other subgroup, provided your subgroup is topped-off, making a single Druid capable of healing the entire squad.Also mentioned above, other classes can provide some of these (Tempest, Herald, Warrior(?) for 25 Might to entire squad, Soulbeast for spirits, other solo-healers, etc.), but almost always aren't as efficient as just bringing a Druid. Some Snowcrows meta compositions actually don't include Druid if they can find a way to provide what the Druid provides more efficiently.Their meta Slothasor composition currently has: Two Alacrity Renegades (one for healing and Alacrity, one to top off Might), these are brought for superior CCDPS Soulbeast for spirits, as healing and Might are already covered by the RenegadesTheir meta MO composition currently has: Boon Thief (healing, 10-target all boons except Alacrity)DPS Soulbeast for spirits, as healing and Might are already covered by the Boon Thieftldr, it's all about efficiency and role condensation. A lot of classes can provide the unique combinations of boons/buffs required for comfortable raid clears, but some classes (such as Druid or Boon Thief) can do it in a much more efficient manner.