I've wanted to make a JJRPG in RPGM2K, (it's the only way I know how to make an RPG) but the Jazz universe as it is simply couldn't carry an RPG: there are too few characters and too thin a plot. Yes, Mario gets RPGs, but by this point (and even when Legend of the Seven Stars was released) Mario has a colossal cast of characters and its more whimsical nature allows it to be an RPG without much of a plot. (Except PM2. That game really surprised me.)