AST's weakness in end game

[Risvertasashi]

CO adds about two refresh ticks for LA, which restores around 10% of your MP. If you're starving, you can line up those two skills 100% of the time. The amount of MP you save from Freecure procs matches what AST saves for lower MP cost for pretty much all healing spells. You can add Ewers to that. You probably have less MP problems with WHM because you're more used to it than you are to AST.

I use the full toolkits of both jobs. The only thing I don't do on your post--I tend to prefer party buffs over self buffs, when RNG permits. Of course, if I really can't do anything else, I'll use the ewer.

edit: To be clear, I don't run out of MP on either job in the course of normal healing.