Just finished story mode. Took about 12 hours.
It's not something I'd consider "ZOMG HORRIBLE" but it was somewhat disappointing. You only get to play as the six new characters in the story, each for only one chapter each (Lightning for 2 chapters). For the last chapter you form a party based on the members, and that is the end of it. The final boss battle is your five members fighting five other antagonist one on one (Garland, Cloud of Darkness, Kefka, Ultimecia, Emperor), then you watch a 5 minute cut-scene and the game ends. Also, the map was a pretty pointless aspect. Why even bother having a map if you can only go in one direction?
And no Cloud or Sephiroth in the story at all, not even a cameo, makes me