First, thanks for showing interest!
While it's true that FFIII is remembered by it's class system, I personally think it's the best FF for NES (If we don't count hacks, of course). Visually looks pretty good for the system, the music while not upbeat and catchy as some of the most well known NES soundtracks are, I think it fits very well, is very melodic, with a serene vibe in most of it's tracks.
There isn't much int he way of the story, but that's okay because you have a lot of freedom to explore. It's also one of the games that added a lot of things to the series, like Moogles, classes like Dragoon or Dark Knight, summons, multiple overworlds and more.
I did like four and a half test playthroughs with different classes and repeating places with different partys trying to get all the problems I could see and fix them.
As far as glitches or bugs, no, not really. I didn't find anything that can be considered one of those. But if you find something weird with my hack please, tell me and I'll try to look into it (Although most of the stuff I did wasn't very advanced so it shouldn't happen).
Although I want to warn you, and anyone that wants to play FFIII (My hack or vanilla, either way).
DON'T USE SAVE FILE/STATE EDITORS FOR ADDING CLASSES TO THE LIST. The save file will corrupt itself, and will f**k up you progress by glitching in two ways:
1º, If you added the classes before leaving the first "overworld" of the game, there will be an event glitch and you will not be able to continue because the game skipped a chunk of the story and you'll have to restart.
2º, If you added the classes after leaving the first "overworld" of the game, and go back to the first overworld (either or items or the several optional things you can do there), when you go back to the normal world, there will be an event reset and you will be sent back to a prior state of it and you'll be stuck forever in that area.
There's also another events that will skip, like when you talk to the Crystals after defeating bosses. So please, bear that in mind. The save file/state editors modify something that it also counts as an event checker, besides the class list.
The half test playhtrough was because of that problem, lol.
By the way, if someone is curious about importing their save files into this hack, you can. You'll need to remove all the pieces of equipment of all the characters, change their classes(as in, Knight->Onion Kid->Knight, if you are going to use the same class), and re-equip everything for all the changes to have effect, though, and if you want to go back to the original, just do the same while running the original version.
You can give feedback if you want, i'm unexperienced with these kind of things, so if you see something that can have it's balance improved, go and say it, as seeing others opinions can help to make a better thing, and knowing how I am, i'm sure I went too far in a few places, or maybe I had to go further in others.
Thankfully the idea of giving a bunch of patches was just for cases in which you don't want everything, or you could do it without something. It also helps making things faster and easier to check.
The palettes are a tough one, because there are not many colors to choose from, and you can't edit each class for itself, it's an entire group of none, so getting a color that works for everybody is kind of difficult.
I think i'll add more colors in the future, if changes have to be made.
Maybe I have to redo the main post and add things...