nothing's definitive in this world, especially not things coming from the modding scene.
the one mod that maybe comes close would be the Atma Weapon mod for FF6. it's mostly complete, fully usable, and a definite, huge improvement over the official release, but i think its makers are still working on it, so it's not definitive still.
there's a bunch of mods for other installments, but not much, and nothing big. there's some WIP stuff too, but it's going slow, as is often the case with these things.