I'm just having a bit of fun with the idea of 'adult' games Real adult stuff is boring and soul draining, lol.
No, I think what we're looking for is that dark -I call it: texture. Like old Disney movies. It contrasts the light, and provides a sense of peril and evil that makes the heroes' adventure meaningful. It's a texture that makes the big picture more interesting. But the fun is still there, the positivity, the charm. I think too many games have 'negativity' or nihilism in them nowadays. That's no fun. It's pretentious most of the time.
But personally, what I'd like to see in JRPGs is mostly design based. More adventure game elements, like the SNES Shadowrun game; solving mysteries, piecing together clues, getting information from characters, finding items to advance the plot or open up new areas. I'd also like divergent quest threads or story threads like in some WRPGs, but maybe not as complicated. Less anime tropes. Different art styles (which ties into less anime tropes). More humble adventures, instead of epics (applies to RPGs in general).