Why is the healer class basically a one spell dps class?

[Eclesis]

If a banned parser is needed to appreciate receiving AST cards, something is very wrong.

Exactly this. Even if there were an official parser if the only feedback you get from your action is a number then it's unsatisfying from a gameplay "feel" POV. Certainly it has no right to be a core job mechanic, something more like a fire-and-forget button like Battle Litany or Mantra (see also: current BRD).

The core gameplay design for DPS jobs in this game is "if you do your job right a Cool Thing happens"; healers are missing that, it's just more Make Health Bars Go Up. Even "simple" RDM, if you do your melee combo right you get to cast Verflare/Verholy. If you balance your mana right it goes up faster. Things you can see and feel without a number telling you so. I don't touch healers anymore but I can tell when I get a card buff on a DPS job, I can even tell what card it was from the sound effects that I still remember from 2 years ago. And it doesn't matter because it makes no discernable difference to my gameplay experience whatsoever. From a DPS POV, in SB if you got a Spear on BRD or Arrow on BLM you def. noticed the effects. Certainly you noticed old Ewer, even Spire. Now? Ehhh. Where's the satisfaction in handing out buffs that are imperceptible to even the recipient, much less to you?