Stormblood was when I joined so that is my frame of reference, so I can't comment on ARR and HW. But in Stormblood, the normal game was still hard, namely the normal roulette dungeons and a few solo duties (namely the RDM 60 and SAM 60 fights). Overworld sadly was just as braindead easy back then as it was today.
I found Eureka overall more enjoyable than Bozja. Eureka had four zones to progress through, so you had more visual variety in environments. Eureka's zones also looked much more visually appealing than Bozja's two brown plains. I liked tiptoeing past the dragons and carefully dropping off the ledges in map 2, and I thought that the really tall ice bridges in map 3 looked cool. But Eureka has better gameplay. You pop in and then you casually pull mobs at your own pace to level up, or you can go set up a NM spawn by killing the correct mobs at your own pace. Sometimes an NM spawns and you might go fight that. Rarely there will be a train that you follow for 30 minutes. But it is overall a chill pace. You have time to look around the map at your own leisure, or shuffle your inventory or tweak your UI, or to alt+tab out and do other things and you probably won't have missed anything essential.
Bozja however had a very frantic and exhausting pace, where there is always FATEs and critical engagements going off. It is go go go with no rest, if you aren't heading to the next FATE before it expires then you are missing out on relic quest items and quest progression. I also did not like the queue and teleport system for the critical engagements, where you queue for some fight that is happening way on the other side of the map and then get teleported there. There is no continuity in geography. I much preferred seeing coordinates posted in my map and then running there and then fighting the mob there. There is continuity. I also liked how it was possible to arrive at a NM as it was being fought, or for people to be able to run away and heal, which made it feel more like a world rather than closed of arbitrary gamey boss fights. I know that the walls are there to prevent zerging/graveyard rushing, but after the first couple weeks of Bozja's release I never saw any Critical Engagements fail.
Stormblood was the last time the story really appealed to me, as it was still about a grounded local geopolitical conflicts in which problems could not be handwaved away. Yeah, you pushed out the imperials, but Ala Mhigo and Doma are still impoverished ruins that will remain as such for at least the next 20+ years. Lots of conscripts coming back to find that their homes are ruins, the people they know are dead, their women having been used up and having grown old, etc. And then the patches were building towards a grim world war in which finally the Empire would bring its full might to bear down on the Alliance, and things were looking dubious. But then that all gets thrown out in favor of a Disney story.