This new version features improvements such as sped up battles, improvements to the Help feature, the ability to dispatch units of 8 characters (instead of 6 previously, though only in high level stages apparently), a raised level and skill cap, and a New Game+ mode.
But that’s not all: Momotaro, the Pheasant, the Monkey, and the Dog are to be playable. There will also be a brand new episode, and the developers are adding a multi-ending system. Finally, there’s a new theme song sung by Orihime (a new character voiced by Yuu Serizawa).
The Famitsu article also mentions DLC, with the following:
an additional story called “Hyuga’s Future”, featuring new types of enemies;
Labyrinth of Yomi, that you can play after clearing the main story. Includes Momotaro and 3 animals, but also multiple endings, various balance adjustments, and more