SO. MUCH. THIS.
But I, and I believe most fans, play them because of the fantastic characters, atmospheric worlds, and of course, the great characters.
Truly great RPGs stand the test of time because they weave fantastic tales with great characters. Nobody still sings the praises of Planescape Torment (to use a WRPG example) because the combat was just awesome, or the graphics blew you away. They remember it and love it because it told a phenomenal story.
I agree to a certain extent, and then I also do not agree.
For example, certainly, Baldur's Gate II had a great story. But, alot of the fun of that game was it's combat. There are people out there still playing that game, because it made you use actual strategy, and because it's fun to try out different things during different play throughs (different classes, skills, party composition, etc) to make the combat new and varied.
And I, for one, actually like turn based combat. I don't think it gets stale. I don't think I'm alone here either. I do realize it's not for everyone. And, if you are trying to attract the largest denominator possible, turn based is probably not the way to go about doing it, sadly.
I will agree though, that the most memorable rpg's, whether western or japanese, were memorable because of the actual story normally, no matter how good or bad the combat was.
On a different note, the term jrpg encompasses a very large and varied amount of games. You have strategy games, turn based games, action games, and games that are somewhere in between. Games that tell huge, complicated stories, games that rely on the mundane, or have little story at all. Games that make you play solo, with no party, or set parties, or games that let you choose your party from an extremely large cast.
Probably one of the few things that was fairly constant was character designs, and even that got alot more varied with the current generation.
I do love games with great stories, but I'm currently replaying Radiata Stories. It's not the most involved or convoluted story ever. The characters amuse me, but they aren't anything special.
The combat was also, rather run of the mill, featuring real time action oriented combat, with different attacks you unlock, and program in as your basic attacks.
What I truly loved about the game, however, was having over 150 characters to recrut, and put in your party. As a side note, I also loved the Suikoden games for the exact same reason (even 3, with it's weaker story)