When your EX gauge becomes full, you enter EX mode, which is a Limit Break-esque state that will power up your character and perform up to four types of transformations. Gil, the currency of the Final Fantasy world, has also been revealed as part of the game but what it does is currently unknown. Gliding has also been shown as a means of movement. Despite its RPG roots, Dissdia's RPG elements are limited to leveling up and choices regarding treasure chests and enemies.
Nomura also assures us the reason the game is taking so long simply because each character has many moves and transformations, and their team wants to make them look perfect. As reported before, there will be 20 characters in the final cast and currently 50% of the game is done. To learn more, the entire article is available here.