I dont know why TVC defends P2 so much, the dungoen design in that game is fucking terrible. I'd take P3 random dungeons over that trash any day.
my biggest complaint with P2 is how annoyingly grindy the whole thing was. want cards? how bout talking to the same monster like 10x times and once you figured out the correct answers for a given conversation, the whole conversation aspect becomes a tedious affair of just finding that particular monster in a battle. you couldnt pass skills from a parent Persona to its child Persona either. not only that but once you summoned a Persona you had to spam the shit out of Fusion Spells for that Persona to grow and get decent in battles. P3 does away with all that crap and if you played your cards right in a fusion, you could have a kickass Persona from the get go, thanks to the boost in EXP it gets from S.Link and the abilities it inherits from its Parents in the fusion.
the dungeon in P2 are 'head scratching' bad, they remind me of Tales of Destiny dungeons, long tedious and not fun unlike SMT3 dungeons or heck even DDS. the underwater lab particularly was a fucking nightmare that almost made gave up on the game the first time.
and after the first full moon battle, you characters rarely get tired from dungeon crawling so it becomes a non-issue. I liked the fact that you could pace yourself and do a lot of sim or go dungeon crawling. it wasnt always talk to NPC #14 trigger cutscenes, go to dungeon rinse/repeat for the whole game. even tho P3 world is pretty damn small I felt it allowed for more freedom, than say DQ8.