Healers do need the ability to deal damage to get through the MSQ... As you are expected to deal damage in various quests, which unironically punishes healers under the current design of things...
And they can't seem to figure out why people don't want to play a healer all that much...

If they gave healers a big nice boost to damage, past (and current) fights would likely lose some difficulty, but if they can then proceed to design fights where all 8 members of the party contribute that might lead to better designed fights.