I like the idea conceptually and think it would be a better progression of what we are currently working with.

Personally, I'd actually like to take damage buffs off the OGCD actions and rework their support to be GCD reliant. I think the way we need to move to make the healers each feel different is to focus in on how they contribute to RDPS and make them fundamentally different from that angle, and I think Astrologian is perfect to create a healer who uses their non-healing GCDs to buff allies and contribute to RDPS through dedicated support--catering to players who don't want to be DPSing as healers, but keeping your contribution interesting and unique. It would have to be raw potency boosts and not percentages.