Oh they can absolutely take healing abilities away. I'll use my AST as an example (I say mine, as in my playstyle as I'm sure other ASTs use some abilities more than I do due to preference)
On the chopping block:
Synastry
Collective Unconciousness
Benefic 1
Neutral Sect
Celestial Intersection
Synastry is a no brainer. It only works on Benefic 1 and 2. The first is useless well before lv50 content the latter we only use when oGCDs are gone and we need single target healing (which is rare). If it isn't going to work with Aspected Benefic (our HoT) CI, ED, and Exaltation, remove it. I would prefer it works with them so
Celestial Intersection *can either lose a charge or lose its place in our kit entirely. AST is no longer a hybrid healer. And honestly it and WHM should lose its shielding. Exaltation fits what CI does better (thematically) and for the most part straight up replaces CI for me (ie I use it for tank busters and TBs in EW come up so little in content I can do so).
Collective Unconciousness is only good to me in 60-70 content and no where else because I don't have as many tools. In EW I can and do ignore it. ES, Horoscope (the occasional Lady of Crowns), and Celestial Opposition do literally everything that I could use it for.
Benefic 1 is obvious. Like Cure 1 it should trait upgrade to 2. Remove Free Cure and Crit Benefic please.
Neutral Sect I would not mind loosing either. I don't use it. Much like Synastry I would prefer if it actually worked on our oGCDs and I don't see why it shouldn't. While under Neutral Sect we could give CO and CI (hence why I have it *'d) back Nocturnal Sect properties instead of it just affecting A. Helios and A. Benefic (we don't need or want the extra healing tied to it). If it isn't going to work on our oGCDs and you aren't going to push us to GCD more.
Obligatory consolidate Draw/Play options into 1 button.
There that is at least 4 button's removal (benefic 1/CU + play options) with CI added if you please (and either move Exalt or make CI into a weaker Exalt and trait upgrade to Exalt) for another 1 (to 5), and arguments made for either changes to Synastry/Neutral or their removal to bump that up to 7 if you wanted.
Plenty of space for a dps button or two.
And as I said, this is MY AST playstyle. Others could make good or better arguments for other skill's removal. I'm not saying all of these should be removed, but what I am saying is that they can be to make room.