I am a "hardcore" JRPG player. My definition of hardcore is anyone who goes out of their way to search game related information for an hour or more.
Casuals just play it for enjoyment, which is fine and all, but they don't want to learn tips and faqs to become better at playing.
Everyone in any gaming forum is a hardcore gamer by my books.
My favorite JRPG series are Disgaea, Ys (any Falcom title works too), Tale Of (Series),
and, of course, freaking PokeManz( Playing the GBA Hacks at PokeCommunity under the username LemonGrass) Stopped.
My definition of RPG is quite general too since it's games that include leveling/grinding and powerups/skills and all the other RPG tropes. This can include genres like Strategy,Tactical, Action, Turn-Based, and several others
My criteria for games:
Story and Gameplay Tied at 1st/2nd One can supplement any enjoyment the other may lack.
Music I like good music. It's one of my draw-ins when choosing noice anime JRPGs and Western games too
Characters Sometimes the story sucks like crap but the characters are very likable.
Replayability This isn't too high on the list because I usually only have time to play one playthough
with my dreaded backlog of several games on many platforms
Graphics is last. Started in GBC/GBA era. PS2/PSP Graphics is considered good to me. PS3 and Wii is fantastic and PS4....can't tell difference.