Square-Enix can get a lot out of this game just by ramping up the nostalgia value associated with past FF's. I remember maybe 2 story quests so far that had the FF2 battle music playing during the battle that got me so pumped! What if we could unlock other FF music that plays at certain times, such as Terra's theme during overworld travel and different battle/boss music?

For that matter, and this is a long shot, but eventually adding non-canonical end-game dungeons featuring stuff like fighting through Pandaemonium to get to the Emperor of Palamecia, climbing Kefka's Tower and fighting the three Goddesses to get to Kefka, a Trial having us fight Sepheroth, all that would be so awesome later on. Do it, SE, whore out the nostalgia factor!