I'd love to see something like Mythic+ dungeons here in XIV, but with the poor linear gear choices we have there's not much sideways wiggle room to give them meaningful rewards, and I don't think they'd be hugely popular without those.

Of late I've come to the conclusion that this game's stale itemization is a BIG part of the reason why our content is so formulaic. Give us gear set bonuses, better secondary stats that actually affect each job in different ways so people build for things that aren't Direct Hit (SB is admittedly better than ARR and HW in this, granted, but improvements can still be made), and IMO work on armor design a bit more and stop shoving the best glamour into crafting only so that glamour farming is realistic even for older content. Do these things and I guarantee the opportunity for fresh content will present itself, since there will be the possibility of "separate but equal or even possibly better" rewards that will entice players into trying it.