Quoting myself from another thread here...
"People seem to assume that "RPG" means a game thats just that, a role playing game. A game where you play a role. As many people pointed out, if thats the case, just about EVERY game is an RPG. Here's the fact though, not every game is an RPG. Choose your own adventures aren't RPG's in the slightest, for example, because playing a "role" is only the most incredibly vague and baseline assumption of what an RPG is.
What makes a game an RPG is that there is some sort of character building aspect to it, usually handled with leveling, and that there's an adventure aspect to it. This is what the RPG genre is. Playing a character role is just what people have perverted it to mean because of the ambiguity in the name of the genre. In an RPG, you have a character. Either pre-made or one you made yourself. As you play through the game, you get to customize/advance this character's stats and customize their equipment. There's also quests to go on, and usually monsters to slay. These are the few things that have remained true to the genre from the beginning, JRPG or otherwise. Having dialogue trees or being able to choose what quests you go on is NOT inherent to the genre, its just something thats become commonplace in recent WRPG's and most JRPG's not made by Squeenix.
Going back to the very origins of the genre, you did very little outside of the main quest except maybe looking for specific ways to improve your character so you're better prepared to handle the main quest. And this wasn't because of limitations because of the systems. This was because you were there to play through the plot thought up by the DM. Sure, you'd have the odd opportunity to do what you want along the way unless he or she was railroading the plot, and you'd have your choice of how to handle the situation and potentially, but in the end you're killing monsters, gaining levels, and eventually going up against the big bad. This is whats at the core of the RPG genre. The typical open world style gameplay of current WRPG's is just a new direction some companies have been taking it. Doesn't make them any more or less an RPG than JRPG's are. So long as you can loot, increase stats, customize your equipment, and maybe save the country/world/whatever, it's an RPG.
By the way, I also want to pose the idea that "role playing game" doesn't necessarily even mean what people think it means. People assume it means playing a character role, but what if the original definition was more about, say, playing a role in a party? That was a big part of the original RPG's (ie. D&D) afterall. Each character had a role to play in the party, and without a proper balance the party would probably fail. So it was a very important factor in these games. Just a little food for thought."
To summarize, I think people get too caught up on the "role playing" part of the genre title. Any game can be a "role playing" game, so its important to consider what makes a game actually part of the RPG genre itself. Looting, adventuring, and customizing stats/equipment are essentially the core basis of the genre regardless of what RPG you're playing.