It seems like the idea might have been to clarify what they want the Healer to be. Focus on healing. The DPS are there for damage.

I'm not saying that's the right move, but it seems plausible to me. As a total non-pro player, but healer nonetheless, I've always tried to weave in as much DPS as the given tank's sturdiness would allow. Sometimes tanks are so solid that I can forget I'm a healer. But there have been a lot of times where I would be DPS'ing and then get yelled at by the tank to only heal. Or the opposite when people would say, "Healer, DPS more!"

There was always this uncertainty. The changes in Shadowbringers just might be the people at SE changing how healers play, with a more clear expectation.