I can definitely see why SH2 is getting hated on. The game feels incredibly rushed especially in terms of pacing and story. I didn't even realize I was on the final level when I got there. Like when I complain about story stuff in Atlus's other latest outings, P5 and SMT5, I can at least say they did a good job of having themes and carrying out on those themes. Literally every theme and story concept in SH2 gets brought up and then never actually expanded on. A huge shame because some of the concepts like the societal stagnation could have been something really thought provoking that stuck with you.
I know everyone goes on and on about the dungeons but besides of some frustration in the later Soul Matrix I thought it was fine if fairly uninspired. I will say I do quite like the battle system. It felt like they took what worked in Strange Journey's battle system and made a massive improvement. Building up the sabbath stack was a lot of fun. I will echo a common criticism that not seeing your demons very much in the fight was a huge mistake. Or at least if that was something you were deadset on not doing, maybe the weapons could've changed depending on who's equipped to who with some varied attack animations... like literally anything. I also, don't know why some things didn't carry over from SMT5 like the physical elemental skills which would've opened up way more builds for the Sabbath system. As is, it doesn't kinda make you value magic way more than physical. I also think the system could've punished you more for hitting enemies with the wrong element.
Atlus has also been progressively worse and worse with DLC. I personally find it easy to ignore the demons and costumes and just pretend they aren't in the game. I unfortunately can't ignore the Lost Numbers dlc though. If you don't get this DLC then you're looking at an incredibly short game for a modern RPG and I don't just mean in terms of hours. Without Lost Numbers you're party only really needs to get into early level 60s at most to beat the game meaning there's a lot of demons in the game you're just never going to need to use. If you're wanting to get the most out of this games content then that DLC is basically a requirement.
Outside of the combat, I did like the core 4 characters. I wouldn't say my enjoyment of those 4 being all that much beyond surface level though. Figue is just the worst though for spoiler reasons. I can't blame anyone for disliking this game but I still found fun in it.

It's always nice to see a game come out a decade plus after the last entry and it not only feels like it didn't miss a beat since then but improves on almost every gameplay decision the previous entries made.
I know a lot people dislike how linear this is compared to entry like Super Metroid but as someone who's both direction illiterate and easily frustrated by not knowing where to go, that's only a plus. My only real complaints with the game are the lackluster soundtrack and some of the QTE boss battle moments being a little unclear when I'm supposed to be shooting while Samus does her cinematic swag on them.

For this playthrough, I did the SEBEC story route.
The way people talk about this game, I was expecting this game to feel a lot more crusty then it actually did for me. Outside of a really sudden difficulty spike near the end that caused me to stop and grind for a few hours and some pretty obvious exploits (you can spam megidola your way out of most battles), I think this holds up pretty well. I really liked the way you have to set your party's positioning on the grid. I was definitely disappointed when I booted up P2 and that was completely removed. Also, I'm not sure if this is an unpopular opinion but the demon negotiation in this game (and P2) might be my favorite way it's handled in the entire franchise. It feels so dynamic to have to match your party's personalities to the demons your trying to recruit (or rather get cards from in this case.)
As for the story, I think it's a pretty simple plotline but I think it's incredibly effective at what it's trying to tell. At least for the plotline I played. I can easily see myself coming back to this game since there's an entire separate campaign, the Snow Queen, to go through as well as just going through the SEBEC route again with different recruiteable party members. One playthrough won't take you long, so if you're even a little curious, I recommend giving the game a shot.
Also, I wasn't sure where to fit this in but to address discourse on the OST, I definitely got the immediate feeling after an hour of playing this wasn't the game's original soundtrack. What's on the PSP version isn't bad. They wanted to make it match P3 which is very far from a bad thing to sound like. It just doesn't work for the game in my opinion. There's a patch out there I'd recommend getting to change it back to ps1 ost. Ideally, if Atlus ever remembers this game exists and does a re-release they'll do the right thing and have both soundtracks available from options.

I'll start off by saying I think this game while earns the praise it gets for it's story. The way the alignment choices don't feel like one or two "good" endings and everything else is the "bad" ending is something that should definitely be more common in the franchise. It's probably my favorite story line in any Megaten game and if Atlus can ever make a new game that matches it's atmosphere again, I'll be ecstatic.
That being said, I really do not care for the gameplay. I like the spirit behind the battle system. You get bonus hits on hitting weakness for every demon in your active party matching your alignment which helps you get in the roleplay. I just don't think it makes for a lot of creative expression in your strategy. Even worse when you factor in how arduous it is to fuse demons with the skills you want in this game. You can remedy this to a degree by going online and using password generators to summon whatever you (provided you got the macca to summon them) but this cheapens it further if you ask me.
I also found the difficulty curve a bit frustrating. For a majority of the game, I found the combat fairly easy. I didn't even consider using the password generator up until the last dungeon. The alignment boss was pretty rough but I made it through with what I'd managed to fuse myself... then I got to the final boss and it was like I skipped an entire dungeons worth of content to prep me for that point.
I'm also going to bring up that the dungeon crawling just felt like a complete choir to me. I know a lot of people complain about classic MegaTen dungeons. I find most of SMT Nocturne to be pretty comfy for example. Strange Journey I was forcing myself most of the time to keep going. The atmosphere each dungeon created was fantastic but in terms of the traps you were going to face were the same annoying stuff each and every dugeon. I especially hated having to rub my face against every wall just in case there was a secret door somewhere.
Anyways, I can definitely see how this game is a lot of people's favorite MegaTen game but it ain't me. There's a part of me that wants to rate it way lower for how much I didn't enjoy the gameplay but I do really think the story, characters, and atmosphere really does a good job of making the experience worth it.