By the way, sidequests weren't introduced in FFIII. The whole class-change thing in FFI could be considered a sidequest (I.E you don't have to do it to beat the game, but it sure makes it easier to do so). And the chocoboo of FFII could be considered a (tiny) sidequest as well, just as finding excallibur (I won't say how, 'cause that's spoiler-ific).