The best ps2 jrpgs:
DDS1+2 - traditional rpg crossed with dungeon crawler with awesome dungeons and a great story. It's toned down from Nocturne, but in its way it's very own beast. Features excellent customization options, especially in part 2.
VP2 - if you want an amazing battle system and dungeon design, probably the best overall ps2 rpg if you want to get down to pure design.
BoF5 is a love it or hate it game. It's a dungeon crawler with emphasis on time management before the time runs out or it's game over. Basically it's Majora's Mask and Dead Rising combined with an rpg with a strategy rpg battle system.
Dark Cloud 1 - Flawed, but interesting game. Beat dungeons to net you rewards to build cities and towns, each with their own personal story, including gay neighbors. Better than the overrated Dark Cloud 2.
Final Fantasy X-2 - Great game that allows unlimited amount of customization. Stay away if you're too self conscious of what you play and/or you take your games seriously.
Final Fantasy XII - Open fields, battles without transitions, great battle system, even better boss fights, immense sense of adventure.
Persona 4 - P3 but better. Better story, characters, better dungeons, better fights, better system flow.
Raidou 2 - Underrated gem. This game is pretty much classic SMT with an action rpg system, and yet the action rpg system is actually really fun in this game. Has some of the best alignment choices in the series, and an awesome demon recruitment system. Personally I almost put it above DDS1+2 but below P3/P4/SMTN but a lot of people I talk to personally think it's the best ps2 SMT next to Nocturne because in many ways it's a back to basics approach aside from the combat.
You've already covered SMTN and you should finish P3.
