It's not really that new of a concept. Many past savage raids have ended with lots and lots of raid-wide aoes that keep the healers on their toes.

I don't normally heal savage, but I healed E2S and they were in that fight and you also had to do a lot of dodging and memorization whilst also healing so the party lived. If you didn't do the dodging and memorization as a healer, RIP, you didn't just die you also potentially wiped the party right before the kill. It also applied damage downs to make it harder to beat the enrage. Don't get me wrong, that was an easy fight overall, but PF would give you the complete opposite impression.