"They are the same, you do not need your full kit"
According to that logic, anyone can claim that every class plays the same way. You do not need to use your full kit. All of us can press only one button. We all play the same. Red and blue are the same. Both of them are colors. Everything is identical.
With all seriousness, how do you expect such type of wrong feedback to be validated by the GMs?
In case you haven't realized after
8 years of playing, normal GCD heals exist to facilitate bad play most of the time. The way to facilitate bad play is the same for every healer. It is bad play, nobody who actually cares about the role uses it, those who don't care also shouldn't complain that they use the same buttons for every healer.
For AST you can be pressing a lot more other buttons while you are pushing your 1 button. People shouldn't be disregarding the healing kits of healers when we are talking dps-ing because
"oh well I have nothing to heal in Satasha". At level cap AST has 5 useful utility spells to press during combat that are not related to healing at all and 8 that are. It is crystal clear that you are meant to be using them in between DPS casts. Something that almost never happens in DF. Gravity & Malefic had their cast time reduced from 2.5 to 1.5s so that you can play your job. Arguing that GMs are disincentivizing healers to DPS makes no sense with the overall changes that they've made. Art of War is instant so that you can heal while DPSing. Holy stuns targets so that you don't have to heal while DPSing. Things are not that exciting when it comes to ST which is something that will most probably change with Endwalker. In the benchmark, you can see Ast casting Malefic IV which means that healers didn't get an actual upgrade of their respective nuke spells, and maybe instead of an upgrade we got another offensive spell. Plus Sage is shown casting a third offensive spell against ST here
https://www.youtube.com/watch?v=IkC1r0eJZ-c&t=321s
That's a spell that was not shown at all in the Sage reveal for reasons unknown.
Play content that does require you to use your entire kit. Savage, ultimates, PvP. Casual content is tuned for casual players.