Are we speaking about costumes? Or about content?
For FF9: Ozma, Gigi, we could also add Cruise Chaser on that list.
For FF7: the ShB trials, the guard scorpions, the gold saucer, possibly the Beehive.
And those are just the ones that are off the top of my head.

While I agree it would be nice to have more, I think the FF4 content was long overdue as well.