I'm not a huge fan of the exploratory zones as a whole but each iteration had its own strengths and weaknesses.

In Eureka you are encouraged to work with everyone else in the instance to coordinate the prep of NM spawns. I found this teamwork fun to an extent, but ultimately you're still just grinding mobs.

In Bozja the NMs have been turned into closed off boss encounters with more interesting mechanics, but you still grind mobs to get them to spawn and to farm clusters. Unlike Eureka however there is no coordination required with anyone else at any point in the zone. If you include the raids there are a couple spots here and there where you have to work together and those are easily the highlights of the entire series. DRS especially was very fun.

If they have another go at this type of content I hope they take the best parts of both iterations.

- The little goals players are working towards should be interesting, whether that be a boss with unique mechanics or some kind of group activity everyone can participate in.

- The method to get to that goal should require communication and coordination between the people in the instance. This should be a place that brings players together in a way other areas typically do not.

Also, I think a lot of times when people talk about missing exploratory zones, what they actually mean (perhaps subconsciously) is that they miss tons of players getting together in the same area to do something as most would imagine when thinking of an MMORPG. I get that feeling myself every time I show up for an S rank hunt. They could add content like this to the normal zones or create an entirely new concept we haven't even thought of, but the main point is getting lots of players in the same place and interacting.

FFXIV is very "shove small groups of people into instances" and I don't know about you but all my favorite memories from past MMOs involve a bunch of players gathering out in the world somewhere. I can talk for hours about things that happened 20 years ago like the battles of Tarren Mill vs Southshore, the opening of Ahn'Qiraj, leveling shenanigans in Valkurm Dunes or Qufim, and so on. Meanwhile in FFXIV I can barely remember what happened last raid tier. FFXIV could definitely use more large scale group content, whether that be another Eureka/Bozja or something else.