The complaint of only spamming a single button has less to do with actual button count and more to do with the lack of interactivity. Reduce the DoT duration to 15s and that solves part of the issue. Have Glare sometimes proc Enhanced Holy and that also solves part of the issue without adding more buttons. Have Dia proc a cooldown reduction on Assize and that also solves part of the issue. Do all 3 of those and you have a decent enough kit without even touching on Glare IV and PoM. It's less about sheer number of buttons and more how they interact with each other; more buttons can give more interactions overall, but you could also just give a 50-button long combo sequence and it'd be just as dull as Glare spam but with 50 hotbar slots instead of 1.
You could add Miasma back to SCH with a 30s timer and I still wouldn't consider that enough for it to be in a state I'd enjoy. Add back Bane and it at least makes dungeons a little more bearable than AoW spam, but still not ideal. If you had Fester on a cooldown that also has cooldown reduction with every broil cast, now you have more to pay attention to and it furthers that old identity of being a DoT based attacker. Even if both Biolysis and Miasma(lysis) were still 30s, Fester with some Broil interaction and Bane would make me want to play it again.