To be fair, Persona 4 has it's fair share of heaviness. Did people forget that the game primarily deals with a serial killer? Sure it's got a lot of sillyness, but some of the scenes are pretty heavy. Saki's death and the confrontation with
come to mind.
And honestly, the other Persona games (with the exception of Persona 3 and Persona 2: EP) are fairly lighthearted.
-Persona 1 wasn't
that dark. Yes, I know I played the remake and it killed the oppressive atmosphere, but when it came to story scenes, the characters and the dialogue were quirky and bombastic (with the exception of Maki scenes). "Hey guys, let's go kick guido's ASS" The characters deal with demons, but they're mostly unaffected by them (with the exception of
-Persona 2:IS is light hearted for like 60% of the game.
Hell, Persona 3's "dismal" tone works against it during some scenes (hi Strega) when they're downright comedic.