This is something I never get: in P4 you supposedly search for a murderer and the progression for every dungeon is:
-"okay, we know who's the next target. Let's keep an eye on them to catch the culprit"
-they find nothing
-"guys, they were kidnapped anyways and thrown to the TV world. We have to save them."
-they save the victim
-"hey, do you remember who kidnapped you?" "Sorry no" "okay"
-they find nothing.
Rinse and repeat until the end of the game. In P5 there's always some sort of progression in the plot. The pacing could be the same in the three games but in P5 the story is always progressing until its conclusion. While in P4 there's no sense of progression other than getting new party members.
Thats not really true though.
During the first arc two people are killed and you and the team end up in the TV world.
Then when Yukiko gets kidnapped they realize that the people who are thrown into the TV can be saved and vow to stop the killer.
With Kanji's arc they realize that the midnight channel itself is signaling who will be kidnapped.
With Rise's arc they actually do think they catch the guy only to find out it was just a fan being stupid.
After that the whole thing with Mitsuo (I think thats his name) happens and they finally 'stop' the killer.
Then Naoto realizes that something doesn't make sense and sets herself up as bait.
Then once Naoto (a real detective) joins the group they really start piecing everything together and barely miss saving Nanako.
The biggest difference is that each time something happens they are learning more and are actively trying to figure out whats going on but in the end these are kids trying to solve a crime once they have Naoto who again is a real detective and she understands how everything has played out they really start to peace it together.
Once thats done you head towards the endgame with the real killer revealed after during everything you they had learned about on its head and realizing that Namatame wasn't the one who killed the first two people.
Even then though the brilliance of Persona 4's story is that all of that might be solved but the 'real' twist has existed right in from of you from the very beginning, the reveal of Izanami is absolutely brilliant and unlike the 'true' villian of Persona 5 is properly foreshadowed ahead of time.
I'm not going to say that the kids never remembering anything about the abduction isn't contrived or plot device to keep the story from moving quicker then it does but it does make sense in context of whats going on, the kids are knocked out unexpected and thrown into a strange TV world, I can at least see how that would screw up what they remember although it would've made more sense if it was ever said that Namatame had used something to knock them out that messed with their memories.