I don't mean to discount it generally; rather, I just don't think it's a good idea to make that unique to a piece of side-content, or even to have it be the first place in which we see that end-game reward. Were interesting materia already pervasive, I'd love to see perhaps some unique (and potentially even faintly, faintly more powerful than elsewhere) version of that thing, but I don't think we should feel compelled by rewards to play the content. Abnormally strong materia would be of consequence to everyone and the fact it's materia (i.e., has a high chance of being destroyed when moved) would add some less-than-fun considerations of hording and upkeep. More importantly, though, materia is iconic to the franchise. Making a single piece of side-content the sole way to acquire an iconic element would give vibes similar to Eureka being the only way to get (the dyable form of) ANY artifact gear (of any expansion, rather than just the dyable form of Stormblood's).
And to be honest, though I'm sure having skills slottable via Materia would warrant complaints as to "illusion of choice" or "adding to the time it takes to have a seemingly functional character", the idea of having a slightly more wind- or storm-centric WHM, and that naturally (i.e., in the course of nightmare dungeon progression) advancing to those materia taking on additional "nightmare" effects, etc., is intriguing to me. Such just has to fight against structural constraints, just as virtually all complex power-effecting progression does. It would suck, for instance, if we had to potentially destroy materia just to swap to a different ability more suited to our content. Hell, if we were to commonly alternate between content types with opposed BiS materia, it'd already be a hassle just to swap between them, however freely. Eventually, you could end up with the "perfect" solution, whereby materia is specific to job and content type and is swapped automatically, or you have Material Palettes (similar to Glamor Palettes) and you can swap out those automatically in accord with certain conditions, etc., etc. But it'd still be a lot of extra investment just to put that power or cool factor you want in an iconic form, rather than just offering it up as Duty Actions or the likes of Lost Actions.
But I digress; the materia idea is long replaced.
Last note: Perhaps I read too much into that, but consider: unless you would otherwise overcap your first-priority secondary stat, a single-stat materia of equal total stat gain will always be better than a half-and-half or equal-thirds or the like.My original idea was maybe that you could get advanced materia such as having 2 stats on it instead of it one.
Given the shift to 8-man, in place of 4-, I'm not sure that would be as possible to just click as an additional option as a simple "Undermanned" (or the aforementioned "Minimum Item Level") option would be. But, regardless, I'm not sure I conveyed my point clearly.Making it so you can just click on nightmare for all current dungeons like you would min ilvl would actually fit in line with more of what i imagined of most of the best rewards being mostly mounts/aesthetics since you would just have access to all dungeons at once without it directly impacting end game too heavily. Each dungeon can have exclusive mounts/aesthetics you can unlock but also a larger pool to draw from as well that all dungeons would share.
By early- and late-dungeon I wasn't referring to, say, ARR or HW vs. Stormblood or Shadowbringers. I was referring instead to when you first start into the dungeon vs. the time by/at which you'd be fighting the last boss. You mentioned before that you expect the difficulty of the dungeon to rise over time, if I recall correctly, and not just in consequence to pull size or the like. If so, the dungeon would get harder over time. The larger that gap, the wider an audience the extremes (the very beginning, or the very end of a speedrun) could appeal to, but the narrower the portion of the nightmare dungeon that would appeal to any given group would be.
My assumption (perhaps faulty) is that you wouldn't be able to just toss in a 'nightmare' mode into any old dungeon (due to its being 8-man), nor that you'd necessarily want to. That seems more the territory of far more simplistic concepts like "unreal dungeons", wherein they'd be synced up (rather than down) and beefed up to be of similar engagement given our skills acquired since the dungeon's original level. Nightmare dungeons seem far more a labor of love, the selection of which would be slowly added to: the likes of visiting an Diablos in an aetheric prison (in which we've trapped him to use as a conduit in whatever "fight fire with fire" plan against the Ascians or by which to discover the means of the end of worlds or whatnot), and then taking any of many portals or mirrors into a tormentuous dreamscape, each, for a selection of dungeons.
If we could have dungeons be both 4-man and 8-man, instead of just 8-or-less (Praetorium, CM) OR 4-or-less (everything else), then yes, a toggle would obviously be better. If not, though, you might want to consider specifically how you want to leverage a rotation of nightmare dungeons or the fact that their parties would basically have to be premades.