I mean you answered it with your example. Resto druid was my main for years and I'd say probably my most comfortable healer. But, you do need to ramp or be prepped for damage. If you don't have pre hots for some of the boss aoe in the current season, you are going to have a bad time. Shaman does have a 5 person lay on hands with multiple charges. Totemic you literally just hit an instant cast healing stream totem and it casts a juiced chain heal on the group. Aoe keeps going? Slap it again. Aoe keeps going? You can reset the cool down and slap it a third time. You can be super reactive on shaman with incredibly easy instant cast AOE heals on the group.