Honestly aside from Spire being almost the go to trash card, I think the AST is in a good place. To me, the whole draw is how versatile it is compared to the other two and how you have options to adjust how you are playing. For example if you are going against slow bruisers you use noct, but if there is a section with a lot of swarming little mobs you can switch to diaural sect so you are being more healing and MP efficient, and then switch back later for the boss. All the while throwing out buffs or setting up buffs as needed for content. To me, it's kinda the real red mage of healing, in that while it may not be a master of any section it has more options then the two classes it's drawing from.

While it would be nice to see some cards maybe used to buff spells, such as maybe using a certain spell with a certain card drawn buffs or augments it....frankly I think AST is pretty much where it should be.