I think u don't need to ask if the DS version of this game worth it... if u are a big fan of this game, will be awesome to play it just even if there is no change at all on the script, items, dungeons, and that stuff... 'cause just seeing ur loved characters in a 3D enviroment is awesome!

Of course, if u are not a great fan of FFIV, u can just play the snes, gba, or ds version with no need to play them all...