Other then the Spells and common monsters, most everything is the same.
Even though they still have a simlar plot (which ususually invoves a guy and a girl falling in love and they have to save the planet) they still are new. I know after about 4 Mega Man games I got kinda tired of it cause they was all the same minus new bosses.
I have been replaying ff10 and it just amazes me Square is the only company that puts such detailed story lines into a game. I mean as good of a game Skies of Arcadia is, it is still generic and nothing compared to a square RPG. While I love the Zelda series even it isn’t AS detailed.