I think Stormblood is the point where older / hardcore players began to see the limits of the current overall system (patch cycle, gearing, tomestones, content). I guess for someone that joined during Stormblood there's plenty to do still. For the others, each patch would give some content for a few weeks (and I remember how 4.3 what pretty much wrapped up in less than a week, and HoH was such a disappointment), then it's back for waiting next patch.
It's difficult for Squeenix to change I guess, because beyond this discontent it's still a safe pattern where people keep their subs active -which is all that matters, technically. I belive thoughg it's time for the game to get some fresh air (like Blue Mage seems to be, but we're not there yet).

Generally speaking, I'd prefer if we had content that travels through expansions, for instance instead of Heaven on High and its most than likely counterpart in 5.35, what if we upgraded PotD with each level cap? What if Eureka didn't lock relic weapon but would offer shiney glamour and its own system (logos mostly), and would be updated on that basis through the expansions.?

My idea / desire is to avoid spending dev resources in re-creating a content that people would label as "reskin of X so I won't do it", give minimal updates to what currently exists, and each expansion could bring something really original (like for 5.0 I'm kinda hyped for Ishgard related announcements).