I think that people saying that they want Eureka/Bozja content to come out earlier are objectively wrong and biased by the fact that the devs never really offered other good alternatives to that.
Each expansion comes out with plenty of midcore content which is under-utilized.
In my opinion the devs should focus on that rather than releasing new content like Eureka/Bozja earlier.
The game has a ton of content which is not incentivized at all and that gets abandoned too fast.

1) FATEs. People keep asking for the relic farm to release earlier. Most of the relic farm is just glorified FATEs.
Rather easy fix: add some NMs in the overworld areas to give them more of an Eureka/Bozja feel and motivate more people to farm FATEs as it would be a bit less monotonous and it would be more satisfying to farm those gemstones instead of the mindnumbing monster bashing it currently is. It doesn't even need to be crazy stuff, just like....take some of the Eureka NMs and copy/paste them in there, you don't even need to invent new mechanics for them really...

2) Maps. Maps are nice but have a major issue in my opinion: the focus on group play.
On one hand, it's one of the strength of this content. It gives a casual thing to do with your mates.
On the other hand, it pretty much forces you to commit to a couple hours of group gameplay.
They should IMO find a way to improve the single player map experience and make them more desirable to farm when you have some free time alone.

3) Hunts...People go on the hunt trains, but I would be really curious to know how many people do their daily hunts, or even the weekly B rank...
The existence of the hunt trains make those pretty much pointless...the xp is nice to get while you wait for a queue to pop, but aside from that they are not worth doing at all IMO...


Other ideas
4) Release a ton more weapons for the new jobs. Meaning, old relics for example, old EX weapons, old raid weapons, old dungeon weapons, etc etc. Breath new life in Eureka/Bozja etc.

5) Not sure if it counts as midcore, but Gold Saucer.
There is not enough new rewards added regularly there. Especially on expansion launch. They added a couple things in 7.1 but not nearly enough.
If they add more regular rewards, they could add some more reliable way to farm MGP other than the weekly lockouts. And people would probably spend more time in there.
(I would personally like a battle square to be added, with gimmick puzzle fights like the Masked Carnival)

6) Release an actual glamour log. That would give a reason for people to farm the new dungeons dozens and dozens of times. Would give a reason to continue farming the normal raids weekly for your alts. etc.