I actually liked P3's story a lot. For what it's worth, I thought the last couple of months made the whole game worth it, so the plot really heats up towards the end, IMO.
It probably comes from jumping right into P3 immediately after finishing P4. IMO P4 really cut away the fat and refined the best parts of P3, making P3 kind of hard to go back to. On the story front, P3 always felt like it was trying really hard to be this dark, edgy, emotional thought provoking masterpiece with a number of out of place anime tropes (because robot girls and shotas are so anime, rite guiz?). P4 on the other hand never really felt like it wanted to be anything but itself IMO. In P4 it felt more like they created a solid cast of characters and came up with an interesting story for them to star in and let the story just be itself.
Which P2 are you playing? I've heard mixed things about both and never know if I should take the leap (same for Persona 1, for that matter).
Eternal Punishment. I'll say this right now do
not play this game if you're looking for something like Persona 3 and 4. P2 is most certainly a Shin Megami Tensei game, not a Persona game. Dungeon crawling is prominently featured, the SMT series' demon diplomacy is a major part of game play and the difficulty is noticeably higher than P3 and P4's (although I will note you the game has two mechanics that you can easily abuse to rip through most fights).
On the story front, your entire parity consists of adults, there are zero school life aspects and the overarching narrative is an end-of-the-world-via-otherwordly-forces type of plot you'd expect of an SMT game. I haven't played Innocent Sin, and Eternal Punishment is pretty obviously part two. The story moves at a breakneck speed, a lot of things are vaguely explained and it seems to trust that you already have a good grasp on things the second you boot up the game. That being said, if you're able to really pay attention the narrative is very engaging, and the entire cast is very likable.
tl;dr: Don't go in expecting Persona as presented by P3 and P4, and you might enjoy it if you like the other SMT games.
