Hacking-wise, very little has been done... It's just that what has been done was done very well. In terms of hacking, I'd say it's less than five percent complete.
The script, however, is good to go.
Off the top of my head...
All text has been translated, but not all of the translated text is integrated into the current version. Menus aren't working due to no small font... In the current version, the menus have been left in Japanese for the sake of playability... All of this text has been translated. It's just been left out of the patcher.
The game needs to have the date-entry screen hacked to allow for more current dates...
There are three "custom strategies" in the Japanese version that can be named by selecting two (of many possible) kanji tiles. These two kanji will appear as the name of the skill in the battle options screen... (All battle options are shown graphically.) This will have to be totally reworked, because it would make no sense in English. I think the best solution is to have pre-set strategy names that cannot be changed by the player. They should only be able to customize each strategy.
Plenty of graphics hacking still needs to be done... Some in battle, but most outside of battle.
Variables don't always display properly, and the game has a tendency to let traces of previously-on-screen text linger in places where it shouldn't... And if an enemy (or skill) name goes past a certain number of characters in the battle window, the name becomes totally invisible.
The credits screen causes the current version of the game to crash, but it can be played through all the way to the end in its current state.
I'm sure there's more.
This project isn't going to be just a couple of brush-ups. Hacking it would be pretty much starting from "Zero."