Here's something that would be cool to do. In WoR, it's possible to re-meet lost allies using an entirely unfamiliar party. The main example is, meeting people with just Gogo and/or Umaro. For instance, Sabin is holding up the house in Tzen, and up walks Umaro, this dumb sasquatch that Sabin's never seen before. And suddenly Sabin and Umaro are having a merry, eloquent conversation like they're best of friends! Off the top of my head, Gogo and Umaro are outright unfamiliar, and it would be possible to make Gau/Mog be unfamiliar at least to certain members.
So the point is, it would be nice if the dialog took this into account.
(As long as I'm dreaming, it would be great if the dialogs in WoR actually checked your party at all. Almost always, the dialogs are just anonymous, and it really shows they were rushing with the deadline and subtracts from FF3's big strength, its abundance of characters)
----------------
On a completely different topic, regarding adding new maps. Is the memory area where maps are stored read-only? I was thinking, and I have no idea how plausible this is, but would it be possible to store extra maps off to the side somewhere, and just swap map data around? For example, the WoB is contained at location A, and your radical new submarine world is at location X. The player submerges the falcon, you *swap* the two maps so now WoB is at location X and submarine-world is at location A? I imagine that probably wouldn't work on the real hardware since the maps are almost certainly read-only, but it's worth asking about