How about....
~1. Party members' locations on the map in real-time like just every other game has already; it's possible. Or add an optional mini-map. If you don't want it, you can remove it. Closing and re-loading the map just to update people's locations gets old.
~2. Status ailment icons...Final Fantasy Tactics, 'nuff said. Tiny little indicators over heads should not kill the game speed, are quicker than typing "Help I got BIOed and I got 25HP", and they were done in 1999. They can be optional, too.
~3. There *should* be a way to edit macros, go to your config menus, access "some things" within reason, of course - while you're KO. That way you can have something to do while waiting for a Raise, so if there was a macro mess-up or something else that perhaps (for example) caused your party to wipe on a BCNM, you could find and fix it right then and there, while it's still fresh in your mind. The "wait for a Raise or HP" option button can be moved, there's no reason to be blocked from my menu just because I have no HP.
~4. Character select screen - Widescreen friendly? Yes? =)

Finally, I realize there is no "perfect UI". I'm not saying to remake it into a masterpiece. I'm saying that bringing it a little more up-to-date would be awesome.