Why not multiple weaker hits raidwides ?

[BabyYoda]

Hello guys, I've a simple question about unavoidable damage:
If we reduce the amount of damage done per hit but increase their frequency, wouldn't it make both healer type more useful ?

Let me explain with an example. (I love using examples)

• Let say the average group member has 10k HP.
• If the raidwide deals less than 10k damage after mitigation, then regen spell is enough.
• If it does more, we can't do it without shields.
• But, if it does 4k damage 3 times in a row, shields would still be useful and direct heals would be too because we could "cast" a heal between the hits. (and spells like adloquium would be very usefull)

If this type of mechanics exist.. sage will be S tier healer