I think they should just rebalance AST to make Sects changeable in battle. We would then have a high skill ceiling healer capable of doing everything other healers can.
1. Raise Nocturnal Sect healing bonus to 10% and change the speed bonus from Diurnal Sect to a 10% MP cost cut for all spells.
2. Change Celestial Opposition to add a 10% speed bonus for 15 seconds when in Diurnal and extend duration of beneficial effects by 10 seconds in Nocturnal, keep it on a 150 seconds cooldown. The stun should be avaiable in both Sects.
3. Divide Collective Unconscious effects between sects: 150 potency/15 seconds regen when using Diurnal, 10% damage reduction/10 seconds when on Nocturnal. Make both effects last after people leave the bubble, just like the regen does now.
4. Lower Aspected Benefic bonus shielding to 25% to adequate it with the Nocturnal Sect new bonus.
5. Lower Luminiferous Aether refresh potency to 50, raise duration to 30 seconds, lower cooldown to 90 seconds. 500 potency refresh every 1:30 minutes, as opposed to the 640 potency every 2 minutes we have now. This would make Astrologian MP more sustainable while DPSing along with the MP cost cut from Diurnal Sect.
6. Change Enhanced Luminiferous Aether trait into Enhanced Aspected Helios - a 15% chance that when using Aspected Helios the next Helios spell will not have a cast time. Make up for the lack of the very niche Cure III and a little help with MP on heavy raid-wide damage fights.
7. Lower Essential Dignity recast timer to 30 seconds.
8. Remove Stella and Combust II cast time to make AST as mobile as SCH while DPSing.
9. Make Aspected Benefic/Helios and Nocturnal Field not stackable (if you have 2 AST they NEED to be each in a different Sect) as well as making Aspected Benefic/Helios and Nocturnal Field not stackable from the same caster (so you can't put a regen on the target, change sects and cast a shield).
This could even make AST + AST a thing and their gameplay would be finally completely different from the other healers.