I mentioned Bad RNG in my initial statement. Why would I mention that if not to insinuate that DoTs would not guarantee Gauge generation? I originally thought about it working that way but due to the number of variables I had to also consider (uptime, GCD healing usage, new players, etc) I figured that I needed to add a contingency or 2 in order to make the system work effectively, hence why Aetherflow and Dissipation were mentioned as well to add onto the System. I only stated 120 because that was your initial argument based on DoTs and Broil alone so I based my argument on yours. DoT uptime is still important though because, despite not being guaranteed, it still helps to build your gauge so ofc I'm going to mention it.
I'm not drawing blanket stats out of thin air here. I'm going based on what you can theoretically achieve thru actually mathing out everything.
In the 1st minute of P4S, you end up using Covenant, Blessing, Dawn and Seraph for a total of 125 Gauge usage. You cast Broil approximately 9 times in that minute for a gauge restore of 45 for a total of 20 gauge, with Covenant and Blessing being off CD already more than likely, and with a 15s gap to build up the gauge for Inverse Chlamys, you should be able to use both for it. Setting the Scene gives you plenty of time to build up the gauge to roughly 75 before any of the mechanics come out and you can utilize Blessing to help during them, while having enough gauge for Seraph again for the Bloodrakes after the 2nd Tank Buster. I could go on but my point is that I already mapped out fairy usage based off of when and where you would need it and when CDs permit, while using only Broil as a means of building gauge (because I can't account for RNG DoT procs). It could work, IF 100% uptime is achieved, which is not something I would force onto any player, especially during prog. DoTs, Aetherflow and Dissipation would all allow a level of leeway with the system so that a SCH wouldn't be screwed with it. So, in theory, you can absolutely compress all of the Fairy abilities into my proposed Gauge system rework.
The reason why I primarily built the system on DPS is because I sternly believe that Healer's toolkits should revolve around a gameplay loop of DPS and Healing feeding into one another. Your DPS skills help you to heal, hence Broil building Fairy Gauge, and your heals benefit your DPS in some way, such as Addlo reflecting damage so as to compensate for not using Broil. I don't really see it as constraining, at least not any more than SCH currently is with its conflicting toolkit.
This is one of my problems with the current healer design. Why use GCD heals at all when oGCDs are so abundant, free and powerful? Shouldn't there be some level of trade off between them to make the choices not so black and white? In your example, Indom is not only more powerful than Succor in terms of healing but also in the fact that it allows you to use Broil to gain DPS over using Succor+Energy Drain and that it doesn't cost 1k MP. What is the benefit of Succor then? A last ditch effort for when crap hits the fan? Why are we content with that? Why is every single suggestion on how to "Fix" healers only geared towards part of the toolkit and not the whole job?They're both used because they are superior and free, respectively.
I admit, I have not shared my entire rework for SCH and without that context, some of my suggestions come off as impractical or, to use your own words, constraining but to receive this level of push back for trying to salvage a horribly underutilized system seems excessive.