Got to the 2nd dungeon at around 8 hours in. Seems like there's either 4 or 5 dungeons total so only 4 or 5 bosses total.
The game starts pretty EO, but as you get further in and get access to more SMT spells/attacks/skills and have more personas to fuse and work with (seems like there's about 180-190 persona) the normal battles get a lot more strategic and dungeon crawling gets pretty fun. You're also not so scrapped for cash or stuck with low max SPs which helps. When quests come in that helps a bit too.
It's still nowhere near as good as a megaten game, but it's a good EO game that's got a strategic Persona-ish battle system and fusion system.
My only complaints are the F.O.E.s and bosses are total fucking boredom HP grinds. The first boss didn't have any weakpoints so it was just chipping away at its health for over 20 mins until it died; endurance boss which is the kind of boss I hate. The first F.O.E. I killed was the same, no weakpoints so just HP grind for 10+ mins. The problem was neither of these fights were challenging in any way other than through endurance because you run out of SP after a while which are the most boring kinds of fights. Pretty worried all the bosses will suck and be a chore, luckily if you don't count F.O.E.s the boss count seems rather low at maybe 5 bosses or so total and that's it. So I'll deal with 30 min boring boss fights a handful of times and enjoy the crawling.
Also the story and banter starts increeeedible dull and skip-worthy since there's not much of a plot to this and what's there is zzz, but when the P3 and P4 crew all combine the banter gets a lot more interesting because it's cross-series interactions and there's some neat moments like how:
spoiler (click to show/hide)
It's revealed that Yousuke from P4's gf was one of the dead victims...so then Ken from P3 pulls him aside and has a heartfelt talk where he questions Yousuke about the morality of revenge vs. moving on.
also some of the P3 cast is cool, some is eh, some of the P4 cast is cool, some is eh, but combined there's a lot of great characters so it gets a lot more fun to watch when everyone's assembled.
Enjoying it at this point. It's not amazing or anything, and I've played better dungeon crawlers (honestly I think I like EO better when it was 2d because everything moved faster) and better megaten, but it's got addictive qualities to it. Will probably be the first EO game I play to the end though if the bosses are just going to be HP chipping I'm going to drop the difficulty for those few fights just to speed things up a bit.