Nostalgically my favorite FF. To this day I still think about it too much.
Brave New World is a fantastic mod with modern balance sensibilities, if you're looking for a reason to do a new play-through. I haven't played it in a couple years at least however, maybe it's changed or gone.
I wrote the first chapter of a fanfic for this game years ago, focusing more on magitek armor combat.
Terra was done dirty.
spoiler
My minimum suggestion for changes should have Kefka still show some interest in her. Like maybe trying to turn her into magicite in Thamasa since she is a half esper. It's implied she was at least something of a toy of his, he went to great length to track her down in the first quarter of the game. It should have been her who shows up on the Floating Continent, with Kefka offering to rule the world with her or something. Dragging back Celes for a 2nd surprise betrayal was always hollow to me, even as a kid. They should've handed the reigns off to Celes at the WoR instead.
Also, for a long time I thought of Terra as a badass from her opening description and how she learns spells without espers, with the finding herself stuff as just window dressing. And then Dissidia forever ruined my impression of her character haha.