After my disappointment with SCH, I decided to look into what other healers got (or lost) and AST ended up attracting me. Looking at some of the complaints: the card system, I didn't play a lot of AST so the changes don't affect me but I very much understand why AST's are complaining, they liked the way it worked and why change it? It's too busy and it doesn't heal so well.
If anybody has seen my SCH complaints they mostly boil down to being bored and healing too well. I missed having to think harder for my heals back in 2.0. So you can imagine seeing complaints like this attracted me to trying AST.
From an outsider perspective, I think the card system is enjoyable. The buffs it gives are stronger than the DNC equivalent at a base level(I am maining DNC at the moment) but may not be as powerful as they were before (with Royal Road removed). 2 min cooldown on Divination seems long, but I kinda get the feeling that was balanced around DNC's Technical Step too, which is a 5% every 2 mins (but gets a DPS move on top). Not gonna lie, it seems like it's an AST version of the DNC buff. Flat damage boosts and a system that's about matching symbols that affects potency. And it works nicely for DNC at least.
But the way I've been rotating it is building unique seals for Divination and then whilst Divination is on cooldown, take advantage of Lord/Lady of Crowns. I felt I wasted fewer cards with this system. Though that could be because I was a less experienced AST, I don't know how much wastage experienced AST's got. Healing was harder than it was for SCH, but I was also a lot busier and I still weaved in buffs and DPS skills and I liked that. A friend did big pulls in a dungeon and whilst I did fear for her life a couple of times, I figured how I might balance AST to keep her alive and still DPS & play cards, as I was determined to do stuff between heals. I DPS'd less mind you, but I also gave DPS boosts to the party SCH and WHM lack. I don't know how that'll differ once I am better at the job.
But coming from a SCH main, it honestly feels like I'm going to prefer how AST plays, without trying to downplay any of the complaints careers AST's have, because they are perfectly valid. What you liked about your job what completely changed and feels underwhelming in comparison to how it was before for you.
At least, these are some of my impressions coming at AST from somebody who didn't main it or play much of it. However, I kinda feel that instead of reworking AST's card system, that effort could have been given to SCH and/or WHM to give them something more to do in their downtime that's not DPS. Thus addressing people's concerns rather than making more of them.