I see two problems with this thread...
- Wrong question: JRPG is a type of RPG, so you can't compare, it's like asking: "do you believe there is a difference between an apple and a piece of fruit." A more accurate question would be: "do you believe there's a difference between JRPG, WRPG, MMORPG and, I dunno, Action/RPG?" Or something like that
- Partially incorrect argument: The "branching story versus linear story" is quite correct, but the "teen angst/annoyance versus serious and dark" isn't. Anyone who ever played a game from Atlus will know what I mean (or Sacnoth/Nautilus for that matter). Instead of comparing atmosphere, compare gameplay mechanics: walking around freely, often using a skill tree or something likewise versus battling in group, often time controlling all characters.