AST is functionally a better WHM with cards, but more specifically, there's really only one card that anyone truly cares about: Balance.

"Utility" is such an umbrella term that you can mean anything with it. Just swap in the word "useful" anytime you want to say "utility" and your meaning won't change. Raid dps buffs are their own kettle of fish, though. Because players (especially in NA and EU) care so much about their personal numbers, any job that can make those numbers look better is going to become very desirable. Gotta bring a DRG for piercing. Gotta bring a NIN for trick. I know you cleared on WHM, but would you mind switching to AST so that we can get some sweet, sweet Balance?

Balancing out jobs that carry these essential dps buffs against ones that just bring big numbers is a complex task. But it's much better to restrict that to being a DPS job balance problem. Healer and Tank balance can get complicated enough without having to worry about these sorts of things.

If anything, the present focus on dps buffing cards actually takes away AST's support focus. If your cards were all about defensive and support effects, it would be a different story all together. Then it would be less about always trying to get that one powerful dps boost for your group and more about trying to get the correct support tool for that specific mechanic. Like imagine if you could hand out a knockback prevention card, for example. That's real support. DPS buffs tend to be a bit one dimensional, and result in one card to rule them all. That's terrible for Balance, in both senses of the word.