Replacement of the Anima system for something that isn't stupid would be the start, after adding chocos and airships.

Choco raising.

About 500 quests to be worked on because there just is no where near the same as other MMOs..

Add some life to the areas by making actual interactive stuff in the environments!

Remove everyones maps and make 'em quest for it or give something like a Fog of War, where they unveil the map by travelling. If they want to have the whole map, they gotta travel everywhere (this coupled with the interactive environments and 500 quests thing)

Add more NMs that do not spawn every 2 minutes >.> try every 2 hours.

About 60 more of each weapon type. Even useless ones to make the cool ones look cooler. ^^