Not a rework from ground up in general, but besides making their dps rotation a bit more engaging again, I think with the inevitable addition of a fourth healer, Astrologians could really have their Regen/Shielding aspect reworked into something else. To me it always felt like this in specific was just some sort of band-aid solution to mend the balance between WHM/SCH.

The perfect scenario to what each healer brings
WHM: No special utility, but extra heals - which may give room for them to dps more freely
SCH: A second pocket healer in the faerie - but they would have to improve her AI and resposiveness
AST: Cards giving buffs to the party
Apothecary*: Potions debuffing enemies

*Or whatever new job