Cleric, Fighter, Druid
I think the cool classes ( cleric, fighter, druid ) have plenty of good healers for class quests.
Monk, Ranger, Sorcerer
The Devs seem to be using costumes to add healers to other class quests ( monk, ranger ) and more healer colors ( sorcerer ).
Survival
Trials of Survival ( Barbarian/ Rogue ) is now the only class quest without a Classic 4* healer ( if you include costumes).
Perhaps Kiril will become a Rogue like Boldtusk became a monk.
Both Rogue class quests have red mobs and bosses.
Barbarian already has a strong Classic 4* blue with Grimm.
The Great Yellow Whale ( apologies to Herman Melville )
They also used costumes to add hitters to some class quests with a lot of utility heroes ( looking at you Trials of Fortitude)