Suggestion for an optional patch:
It's just a personal opinion, but I don't like the FDS battle music as much as the NES version, and I'd prefer to have the NES version play in all overworld battles. So perhaps make two optional patches for the battle music. One in which the NES battle music plays in all overworld battles no matter where you are in the world, and another for the FDS version for those that like this song. People who like both songs can just ignore these patches and play the romhack as normal.
I'll consider this for next week. Shouldn't be hard to do.
Outside of that, a while ago I tried doing some debugging to see if the experience gained could be saved to SRAM per-savefile, so each save slot saved the Exp. and you didn't start from 0000 each time.
I did manage to make the game save the Exp, but weirdly enough, it seems the Exp saved is stored for all 3 save slots, not just one.
I found this really weird, it seems the Exp needs to be cleared after death or reset, or else the previous Exp amount will get loaded into whatever saveslot you load next.
I didn't manage to find anything else, as that's where I stopped, but certainly making the game save the Exp per each individual slot would be something of interest, even if it's just a curiosity of mine.