Well, I'd like to see what better extra features (in-game so not stuff like the bestiary and music player) you could implement in FF2. Also, the personalities of most of the characters in Soul of Rebirth weren't really as fleshed out as they were in the main game (except for Ricard's). Also, a side story of the characters that perished seems to fit more for FF2 than the features in the other Advance remakes like swapping team members (you could only swap in two other members, Gordon and Leila, unless they let you use Pavel which would be strange) or a bonus dungeon (I don't know why but a Bonus Dungeon in FF2 seems weird to me).

As to not let this thread go off topic, I'll respond to your question about Dissidia in your usernotes.