When you reset time you keep any major items, warp points and learned songs. The best way to tackle a dungeon is to reset and slow down time and then take on the dungeon from the very beginning of that cycle.You generally get access to a dungeon by completing a quest and learning a song. You just need to do this quest once and when you reset time you can just warp to the dungeon and play the song.
As I understand it getting 2 dudes to record a thing almost every day takes a tole on the schedueling they can't afford. Recording a metal gear scanlon whennever Dan and Drew are available seems more manageable.
Endurance Runs were never recorded every single day. They did a few long recording sessions and then cut it into separate parts. It's really apparent in the P4 ER as Vinny keeps making jokes about it.
I liked the game, but was disappointed with it, especially because of the battle system, with the broken AI, the repetitive structure of the story, with the emotion collecting, and the overworld, that for a game that relied so much on charm, having a isometric perspective on the overworld killed part of the magic.
Those are pretty much my feelings on it as well, though I didn't mind the overworld too much. The sidequests are terrible and the battle system is really clunky especially with the cinematic attacks the bosses use that cancel out anything you were attempting to do. I enjoyed the atmosphere but after the second town they really seemed to cut back on production values.