AST is Time Mage is the issue though.
Delayed healing and regens to me = that. Macrocosmos especially since it seems to Rewind health. (the effect even looks like a clock) And they're called Heals over Time. Quite frankly you could remove the cards from AST and it would be Time Mage the Healer.
Also, I can't say it would sit well with many people who played AST who HAD Time Dilation for it to be removed and then given to a mage who technically could fill AST's role. Espeically since people want a Time mage with delayed damage. Uh... you could literally drop that into AST with 0 problems since Earthly Star exists...
AST unfortunately is bloated with concepts from fortunetelling to time magic.
As it stands right now, without Noct Sect, you'll hear me double down on AST being regen/delayed healer based. It literally fits all of its heals outside of its base lv50 kit: CO - regen. CU - regen + mit. Horoscope - delayed heal. Macro - delayed heal. Exalt - delayed heal. Earthly Star - delayed heal.
AST is a manipulator of fate and arguably time. May as well keep it.
If we wanted to make room for a 5th healer (which considering SGE I don't think SE could even DO), make AST stance dancer between Di/Noct and have the final healer be a HoT based one I guess.