It was OK, but it came at the expense of it being some of the worst-designed relic systems we've had, the Resistance relics were designed with not an ounce of longevity in mind with the underlying content, being relegated to effectively the same treatment as Bozja wherein you're almost encouraged to use Discord etc., to even have a remotely pleasurable experience with the relic. Was OK on patch, but it very quickly started to show its colours and I can say had I not gone through the process of getting them all in the same expansion as their release then I would not be hard pressed going for them, and this is someone who is actually enticed by achievement points.
ARR I have mixed feelings for. If I were to be told it's the worst relic I'd be inclined to agree with some measure, but if they were to say it had no potential then I'd disagree vehemently. in fact, the books were a great system, they just need(ed) to have a system like Wondrous Tales, aside from that it had people doing almost anything and everything so it was difficult. Relics should be like that rather than FATE-farming simulators exclusively, which arguably Eureka was.
By the same extension with respect to PotD, the exact same argument could nearly enough be made in the case of Heaven of High, and not only this if you were to actually compare the Exploratory content of HW (Diadem) to that of Eureka Anemos and Pagos, you will largely find that if you were to have slapped HW relic weapons inside of Diadem then you would find an experience not too far from that Anemos or Pagos, so I don't really think you need to look too far from Stormblood to see the pivots made in the copy paste department when HoH didn't really evolve much in the area from PotD, we had, a dog with an AoE buff, and some magicites that were innovated upon. Outside of that, it was a copy-and-paste experience. The same again could be said if you were to look at the original Diadem and how well it maps to Eureka Anemos and Pagos, bar the leveling system behind it.
If I am being frank, I didn't really find much in the way of elaboration or difficulty with respect to the HW alliance raids, and similarly, the SB alliance raids just felt like sponges. I felt more like I was playing the game of 'how long before the lala falls asleep' (Given that was my char at the time) If you think HW crafting was a staple of any form of sophistication then I don't really know what to tell you.
Eureka Anemos is just as shallow as any other content we've had, and similarly is the case with Pagos, as per my earlier paragraph being a system that was introduced as early as HW in the most basic form, yet the only difference, was, what? Stripped of the aesthetic and remodeled with a leveling system included. The fact this was all they could do even with already having Diadem as the base structure (which included an emergency mission), only serves to show how disappointing Anemos and Pagos actually were, and far, far worse than Island Sanctuary, I would argue. With respect to Eureka/Bozjan-style content that should not be the requirement to introduce 48-man content, or content similar. Furthermore, they should not need to keep this rote formula, especially with your acknowledgment that they started crap and ended out fine. There's no reason they couldn't expand this self-same system to Criterion/Variant with the logos etc., Or have it separate from exploratory content entirely. Given you've stated Eureka and Bozja leads me to believe that the exploratory content itself didn't take your intrigue just the fact it had a large-scale raid included, and some nuance with the logos/essences system - Which I'll be frank with you, is a good system, but it is also a system that has come long past the date of being tied to a particular piece of content, and I would argue should be more applicable to the wider scope of content rather than should be part of x.
They should be looking at newer things, now granted, I don't think this should directly come at the expense of all content, e.g., I still think the expansion should have a 48-man raid. But I don't think every expansion should have x and y (e.g., a Bozja and Eureka) that's very quickly just running into a copy-and-paste job, this is why I was highly against deep dungeon, because I think they long, long hit their creativity with that, or are willing., but if they can at least cycle it without, again, necessarily coming at the expense of 48-man raids then that's a good state.